A161801 G.f. is Q_0(q) where Q_0(q^4) is a series quadrisection of the g.f. of A161800.

1, -6, -8, 112, -86, -752, 1360, 1216, -5384, 10762, -8176, -59888, 130160, 47696, -306336, 485952, -632982, -1582304, 4638088, 343120, -6514672, 8034464, -16636656, -20670528, 82724176, 17877578, -114481936, 52539968, -178638656

Offset

0,2

Comments

The g.f. of A161800 has two nonzero series quadrisections; the other is given by A161802.

Links

Table of n, a(n) for n=0..28.

Example

G.f.: Q_0(q) = 1 - 6*q - 8*q^2 + 112*q^3 - 86*q^4 - 752*q^5 + 1360*q^6 +...

Prog

(PARI) {a(n)=local(L=sum(m=1, 4*n, 2*2^valuation(m, 2)*sumdiv(m, d, -(-1)^d*d)*x^m/m)+x*O(x^(4*n))); polcoeff(exp(L), 4*n)}

Crossrefs

Cf. A161800, A161802.

Sequence in context: A013237 A013234 A013240 * A211041 A236754 A069660

Adjacent sequences: A161798 A161799 A161800 * A161802 A161803 A161804

Keyword

sign

Author

Paul D. Hanna, Jul 19 2009

Status

approved