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A212283 First a(n) > 1 such that its sum of digits is the same in base 2 as in base n 1
2, 6, 4, 6, 12, 21, 8, 10, 20, 12, 14, 172, 30, 46, 16, 18, 36, 20, 22, 126, 46, 24, 26, 126, 28, 30, 58, 60, 120, 126, 32, 34, 68, 36, 38, 185, 78, 40, 42, 126, 44, 46, 90, 92, 138, 48, 50, 246, 52, 54, 106, 108, 56, 58, 114, 60, 62, 120, 182, 126, 188, 378 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

Theoretically, there might exist an n for which there is no solution, in which case a(n) would be set to 0 by convention; however, no such case was found so far. Problem: does it exist?

LINKS

Stanislav Sykora, Table of n, a(n) for n = 2..10000

EXAMPLE

Example: a(13) = 172 because 172 is the first number >1 such that its expansions in base 2 (10101100) and in base 13 (103) have the same sum of digits, namely 4.

MATHEMATICA

sdn[n_]:=Module[{a=2}, While[Total[IntegerDigits[a, 2]]!=Total[ IntegerDigits[ a, n]], a++]; a]; Array[sdn, 70, 2] (* Harvey P. Dale, May 29 2013 *)

CROSSREFS

Cf. A037301, A212222.

Sequence in context: A059773 A127399 A240751 * A247566 A151689 A216833

Adjacent sequences:  A212280 A212281 A212282 * A212284 A212285 A212286

KEYWORD

nonn,base

AUTHOR

Stanislav Sykora, May 08 2012

STATUS

approved

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Last modified May 23 04:09 EDT 2017. Contains 286909 sequences.