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Base-2 logarithm of denominator of (Sum_{k=0..n^2-1} (-1)^k*sqrt(Pi)/(Gamma(1/2-k)*Gamma(1+k))) - n.
3

%I #23 Dec 12 2023 18:28:07

%S 0,4,15,26,46,67,94,120,158,194,236,281,333,386,445,502,574,642,716,

%T 792,875,960,1054,1143,1244,1345,1451,1560,1676,1793,1916,2036,2174,

%U 2306,2444,2584,2731,2880,3034,3190,3356,3519,3690,3862,4041,4226,4413,4597,4796,4992

%N Base-2 logarithm of denominator of (Sum_{k=0..n^2-1} (-1)^k*sqrt(Pi)/(Gamma(1/2-k)*Gamma(1+k))) - n.

%t f[n_] := Log2[ Denominator[ Sum[ Binomial[2m, m]/4^m, {m, 0, n^2 -1}] -n]]; Array[f, 50]

%Y Cf. A280656, A007814.

%K nonn

%O 1,2

%A _Ralf Steiner_, Apr 13 2017