A365840 - OEIS

%I #10 Sep 20 2023 10:01:22

%S 1,6,55,602,7263,93192,1247636,17230290,243669007,3511010950,

%T 51361157967,760784343128,11387857096900,171988619895216,

%U 2617571721008520,40105744064042626,618116513218831407,9576289414539654450,149053521972041737413

%N Expansion of (1/x) * Series_Reversion( x*(1-x)^4/(1+x)^2 ).

%F a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(4*n+k+3,k) * binomial(2*(n+1),n-k).

%o (PARI) a(n) = sum(k=0, n, binomial(4*n+k+3, k)*binomial(2*(n+1), n-k))/(n+1);

%Y Cf. A032349, A365839, A365841.

%Y Cf. A278745.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Sep 20 2023