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 wu :: forums    riddles    general problem-solving / chatting / whatever (Moderators: Eigenray, SMQ, towr, Grimbal, ThudnBlunder, Icarus, william wu)    2017 « Previous topic | Next topic »
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towr
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 Re: 2017   « Reply #25 on: Jan 3rd, 2017, 10:20pm » Quote Modify

Oh yeah, wolfram alpha interprets log() as ln(), but it does have log10().
I suppose I could try to find ones without log. One the one hand, it does supply the function, but on the other hand only in a form that contains digits.

And in many cases I need to put parenthesis around percentages, so 94 = (2^0) / (1%) - totient(7)  should work.
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 Re: 2017   « Reply #26 on: Jan 4th, 2017, 7:05pm » Quote Modify

Aah, an international pool of (interdisciplinary) confusion - logarithmic notation ...

Separately, not hugely interesting, just some trivia I thought of while driving: if we construct a sum of powers of two then we get a nicely ordered set of initial odd integers:
22 + 20 + 21 + 27 = 135

The sum of (decimal) digits in bases 2 and 6 are equal (to 7), ditto bases 3 and 5 (9):

(2017)2 = 11111100001, sums to 7
(2017)6 = 13201, sums to 7
(2017)3 = 2202201, sums to 9
(2017)5 = 31032, sums to 9
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towr
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 Re: 2017   « Reply #27 on: Jan 4th, 2017, 10:35pm » Quote Modify

In bases 10, 19, 22, 25, 29, 33, 37, 43, 49, 57, 64, 73, 85, 97, 113, 127, 145, 169, 225, 253, 289, 337, 505, 673, 1009 the digits sum to 10 (in the same base)
e.g 201710 = [1][1008]1009 => 11009+10081009=101009 = 100910
 « Last Edit: Jan 4th, 2017, 10:59pm by towr » IP Logged

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