A161802 G.f. is Q_1(q) where q*Q_1(q^4) is a series quadrisection of the g.f. of A161800.

2, -16, 18, 176, -544, -160, 2834, -5104, 3232, 18032, -68992, 48400, 143074, -343088, 461344, 63888, -2298880, 2963520, 1387424, -5145536, 10416514, -9297312, -31084704, 42991712, 34760672, -51170800, 81567168, -94111088

Offset: 0

Author

Paul D. Hanna, Jul 19 2009

Keywords

• sign

Comments

The g.f. of A161800 has two nonzero series quadrisections; the other is given by A161801.

Examples

			G.f.: Q_1(q) = 2 - 16*q + 18*q^2 + 176*q^3 - 544*q^4 - 160*q^5 + 2834*q^6 +...
		

Crossrefs

Cf. A161800, A161801.

Programs

PARI

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