A023104 (2^n)-th digit of infinite string 12345678910111213141516...

1, 2, 4, 8, 1, 2, 3, 6, 1, 0, 3, 1, 0, 2, 7, 6, 5, 4, 0, 9, 1, 4, 7, 1, 5, 5, 7, 0, 2, 5, 1, 5, 5, 5, 0, 4, 8, 1, 9, 0, 2, 2, 1, 0, 5, 6, 8, 1, 9, 1, 8, 2, 3, 5, 4, 4, 4, 3, 8, 7, 0, 0, 6, 3, 1, 2, 1, 5, 5, 0, 1, 1, 5, 9, 9, 3, 0, 1, 6, 4, 9, 1, 2, 5, 1, 8, 4, 3, 1, 1, 7, 2, 5, 7, 9, 6, 6, 7, 4, 9, 7, 1, 7, 0, 0, 3, 5, 0

Offset

0,2

Links

Table of n, a(n) for n=0..107.

Formula

a(n) = A007376(2^n). - Robert Israel, Jun 27 2014

Mathematica

almostNatural[n_, b_] := Block[{m = 0, d = n, i = 1, l, p}, While[m <= d, l = m; m = (b - 1) i*b^(i - 1) + l; i++]; i--; p = Mod[d - l, i]; q = Floor[(d - l)/i] + b^(i - 1); If[p != 0, IntegerDigits[q, b][[p]], Mod[q - 1, b]]]; Array[ almostNatural[2^#, 10] &, 105, 0] (* Robert G. Wilson v, Jun 27 2014 and modified Jul 15 2014 *)

Crossrefs

Cf. A007376, A033307, A023103.

Sequence in context: A010743 A072032 A365814 * A133145 A350208 A317414

Adjacent sequences: A023101 A023102 A023103 * A023105 A023106 A023107

Keyword

nonn,base

Author

David W. Wilson

Status

approved