A238717 Sum_{k=0..n} C(2*k, k)^n.

3, 41, 8225, 24171313, 1017938927841, 622602106165767361, 5608871461647356879321985, 752730443089043674648784110740481, 1518229276131523691441191545330131883774977, 46343219682310810626560369524452971573580502826086401

Offset: 1

Author

Vaclav Kotesovec, Mar 03 2014

Keywords

• nonn

Crossrefs

Cf. A211610, A211611.

Programs

Mathematica

Table[Sum[Binomial[2*k,k]^n, {k, 0, n}], {n, 1, 20}]

Formula

a(n) ~ exp(-1/8) * 4^(n^2) / (Pi^(n/2) * n^(n/2)).