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 A355071 G.f.: Sum_{n>=0} a(n)*x^n/(n!*4^(n*(n-1)/2)) = log( Sum_{n>=0} x^n/(n!*4^(n*(n-1)/2)) ). 2

%I #13 Jun 18 2022 13:59:55

%S 0,1,-3,81,-13311,11688705,-51334027263,1082183686000641,

%T -106464672910860746751,47880898685034024043741185,

%U -96901748928702482338511172665343,871602415363671863767026450797790494721

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

%F a(0) = 0; a(n) = 1 - Sum_{k=1..n-1} 4^(k*(n-k)) * binomial(n-1,k) * a(n-k).

%o (PARI) a(n) = n!*4^(n*(n-1)/2)*polcoef(log(sum(k=0, n, x^k/(k!*4^(k*(k-1)/2)))+x*O(x^n)), n);

%o (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=0; for(i=1, n, v[i+1]=1-sum(j=1, i-1, 4^(j*(i-j))*binomial(i-1, j)*v[i-j+1])); v;

%Y Cf. A134531, A355070.

%Y Cf. A137435, A355074.

%K sign

%O 0,3

%A _Seiichi Manyama_, Jun 18 2022

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Last modified June 8 10:57 EDT 2023. Contains 363164 sequences. (Running on oeis4.)