A137158 - OEIS

%I #2 Mar 30 2012 18:37:09

%S 1,4,22,228,4749,200240,17034964,2913479848,999402129243,

%T 686662003846640,944294243796543974,2598186366278914473948,

%U 14300408328085246335179009,157434326611214704329370130880

%N G.f.: 1 = Sum_{n>=0} a(n)*x^n/(1+x)^(4*2^n).

%C Equals unsigned column 2 of triangle A137156.

%o (PARI) {a(n)=polcoeff(1-sum(k=0, n-1, a(k)*x^k/(1+x+x*O(x^n))^(2^(k+2)) ), n)}

%Y Cf. A137156; A001192, A137157, A137159, A137160.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Jan 24 2008