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A054131
T(2n,n), array T as in A054126.
0
2, 5, 24, 134, 802, 4960, 31212, 198504, 1271754, 8192780, 53009614, 344213930, 2241814696, 14637778784, 95786210880
OFFSET
0,1
FORMULA
a(n) = A052509(4*n,3*n+1) + A052509(4*n,n) = 2^(n-1) + Sum_{m=0..n} binomial(3*n,m). for n >= 1. - Jianing Song, May 30 2022
PROG
(PARI) a(n) = if(n==0, 2, 2^(n-1) + sum(m=0, n, binomial(3*n, m))) \\ Jianing Song, May 30 2022
CROSSREFS
Cf. A054126.
Sequence in context: A208969 A020022 A026073 * A086635 A020124 A012249
KEYWORD
nonn
STATUS
approved