1,27

Sequence has the same parity as A000041, the partition numbers, i.e. a(n) is congruent A040051(n) mod 2 (proved by James A. Sellers using generating functions).

Table of n, a(n) for n=1..85.

(PARI) a(n)=polcoeff((1-x)*prod(k=1, n, 1+x^(2*k+1), 1+x*O(x^n)), n)

Sequence in context: A127505 A194923 A321103 * A342003 A339737 A089650

Adjacent sequences: A086369 A086370 A086371 * A086373 A086374 A086375

sign,easy

Ralf Stephan, Sep 06 2003

approved