A381291 - OEIS

A381291

Number of subsets of 8 integers between 1 and n such that their sum is 0 modulo n.

1, 5, 15, 43, 99, 217, 429, 809, 1430, 2438, 3978, 6310, 9690, 14550, 21318, 30666, 43263, 60115, 82225, 111041, 148005, 195143, 254475, 328755, 420732, 534076, 672452, 840652, 1043460, 1287036, 1577532, 1922740, 2330445, 2810385, 3372291, 4028183, 4790071

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OFFSET

9,2

REFERENCES

Sequence studied in: Number of partitions of modular integers, by David Broadhurst and Xavier Roulleau (in preparation).

LINKS

Table of n, a(n) for n=9..45.

FORMULA

G.f.: x^9*(1 + x - x^2 + 7*x^3 - 4*x^4 + 6*x^5 + 4*x^6 - 4*x^7 + 3*x^8 + 5*x^9 - 3*x^10 + x^11)/((1 - x)^4*(1 - x^2)^2*(1 - x^4)*(1 - x^8)).

EXAMPLE

For n=10, there are a(10)=5 order 8 subsets of Z/10Z with sum equal to 0 mod 10.

CROSSREFS