A086372 First differences of A027349.

-1, 0, 1, -1, 1, -1, 1, 0, 0, 0, 0, 1, -1, 1, 0, 1, -1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 2, 0, 1, 0, 2, 1, 1, 0, 3, 1, 1, 1, 3, 2, 1, 2, 3, 3, 2, 2, 4, 5, 1, 4, 5, 5, 3, 5, 6, 7, 4, 6, 8, 9, 5, 8, 11, 10, 8, 10, 13, 13, 11, 12, 17, 17, 13, 16, 22, 19, 19, 20, 26, 26, 23, 25, 33, 32, 29

Offset

1,27

Comments

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).

Links

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

Prog

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

Crossrefs

Sequence in context: A321103 A358133 A363878 * A342003 A339737 A364916

Adjacent sequences: A086369 A086370 A086371 * A086373 A086374 A086375

Keyword

sign,easy

Author

Ralf Stephan, Sep 06 2003

Status

approved