Powers of two

[ciphergoth]

I can't remember what made me think of this, but there's a bit in Snow Crash about powers of two, and I wondered if things had changed, and that people deal in higher level stuff than this these days. And it's just striking and a bit weird anyway that some people have had occasion to memorize this stuff, I wondered if you had...

[Poll #1217360]

Update: The "powers of two" are just 1+1 = 2, 2+2 = 4, 4+4 = 8, 8+8 = 16 and so on.

Update: it seems like it isn't clear from the above, so for the avoidance of doubt, no-one should feel that they should know this off by heart!

Comments

It's easy

[babysimon]

0x00000001
0x00000002
0x00000004
0x00000008
0x00000010
etc

;)

[alextiefling.livejournal.com]

All except the one that's got the form 32xxx; I can calculate that it must in fact be 32768, but I always forget it when listing them.

[valkyriekaren.livejournal.com]

No, I get stuck somewhere in the mid-hundreds, but that's dyscalcula for you - I can't cope with numbers more than two digits long.

[damerell.livejournal.com]

Almost. "Ha, he means 65535, what a... no, wait."

[olethros.livejournal.com]

Admittedly, I go a bit fuzzy after 4096.

[stgpcm.livejournal.com]

no, 16Ki and 32Ki escape me

[kimble.livejournal.com]

Have to stop and think for a second to get the last two, but basically, 'yes'.

[wildeabandon.livejournal.com]

Apparently I can only do up to 12 completely off the top of my head, although the time lag between recalling from memory and calculating the other four is scant seconds.

[thekumquat.livejournal.com]

I'd probably only recognise up to 4096. Although once when I was about 6 I set out with vast reams of computer printout paper to calculate how many grains of rice went on the final square of the chessboard. I think I got up to square 40 or so before getting bored of multiplying by two by hand...

[elsmi.livejournal.com]

16384 is my only shaky one.

I note that right now the poll responses look like: 15, 7, 1. Which is nice.

But does anyone know 2^17?

[selectnone.livejournal.com]

I get fuzzy after 8192.

Textures for games usually have power-of-two resolutions, and that'd be at the silly end of the image-sizes I'm likely to touch.

(actually, 64x64 is a largish texture for the game I'm working on right now)

[phantas.livejournal.com]

Computational Number Theory does that to you. I also know or can quickly compute in my head way to many squares, primes, factorisations and square-roots. Back in my teens I computed square-roots with <1% error by head as a party trick (really, it's *way* more easy than it sounds)

[phantas.livejournal.com]

I can tell you that 2^17 - 1 is not a prime

ETA: arg, sorry, shouldn't make claims of (non) primality at 1h30AM.

[mskala.livejournal.com]

There's an amusing story in one of the Feynman autobiographies about a human-versus-abacus cube root contest.

[zwol.livejournal.com]

131072. I think.

Re: It's easy

[uke.livejournal.com]

What's wrong with

1
10
100
1000
10000
100000
1000000
...

?

[uke.livejournal.com]

heehee!

[marnanel.livejournal.com]

To my alarm I find I don't:

1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 163oh dammit, 32768, 65536.

The others I can reel off like telephone numbers. Better change my vote.

[marnanel.livejournal.com]

16384 is my blind spot too! I wonder whether it's more common than other numbers in other people?

I also can't put that sentence together.

[ephermata.livejournal.com]

I can recognize more easily than I can generate, but the lower ones up to 4096 I know reasonably well. They just seem to pop up all over the place, that's all.

[elsmi.livejournal.com]

Correct -- you win an internet! (Formatted as a pcap dump file, natch -- you get to decode it yourself.)

[aster13.livejournal.com]

I don't know what one is. :(

I was an oddity in high school - top sets for science (extra classes and everything!) and third set for maths. No one else was in anything less than top set for maths.

[wechsler.livejournal.com]

At this time of day I stop at 16384, although I feel I should be able to get to 65536 normally.

[ciphergoth.livejournal.com]

You can't edit polls, so I would have looked very foolish if I'd got that one wrong!

[ciphergoth.livejournal.com]

I was trying to work out which of the women on my FL would answer "yes" to this, and you were the one of whom I was most certain :-)