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A336955
a(n) = Sum_{k=0..n} k^k * binomial(n, k)^2.
0
1, 2, 9, 73, 849, 12651, 228493, 4836301, 117204545, 3196763983, 96842596701, 3224356269597, 116981406934417, 4591908332288837, 193846634326107701, 8755364023207809301, 421214258699748184321, 21500563181275847468503, 1160430732790051008442141, 66020998289431649938896445
OFFSET
0,2
MATHEMATICA
a[n_] := 1 + Sum[k^k * Binomial[n, k]^2, {k, 1, n}]; Array[a, 20, 0] (* Amiram Eldar, Aug 09 2020 *)
PROG
(PARI) {a(n) = sum(k=0, n, k^k*binomial(n, k)^2)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 09 2020
STATUS
approved