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A068034 Number of subsets of {1,2,3,...,n} that sum to 0 mod 13. 1
1, 1, 1, 1, 1, 2, 5, 10, 20, 39, 79, 158, 316, 632, 1262, 2522, 5042, 10082, 20164, 40330, 80660, 161320, 322638, 645278, 1290556, 2581112, 5162224, 10324444, 20648884, 41297764, 82595524, 165191048, 330382100, 660764200, 1321528400 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

LINKS

Table of n, a(n) for n=0..34.

FORMULA

Empirical G.f.: -(2*x^13-x^10+x^9-x^6+x^4+x^3+x^2+x-1) / ((2*x-1)*(2*x^13-1)). [Colin Barker, Dec 22 2012]

MATHEMATICA

Table[Count[Subsets[Range[n]], _?(Divisible[Total[#], 13]&)], {n, 20}] (* Harvey P. Dale, Feb 14 2012 *)

CROSSREFS

13th row of A068009.

Sequence in context: A001629 A159230 A181366 * A222082 A327287 A296122

Adjacent sequences:  A068031 A068032 A068033 * A068035 A068036 A068037

KEYWORD

nonn

AUTHOR

Antti Karttunen, Feb 11 2002

STATUS

approved

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Last modified April 21 15:39 EDT 2021. Contains 343154 sequences. (Running on oeis4.)