A374880 Obverse convolution (floor(3n/2))**(floor(3n/2)); see Comments.

0, 1, 18, 256, 5400, 117649, 3359232, 100000000, 3643149312, 137858491849, 6126151500000, 281474976710656, 14777503265582208, 799006685782884121, 48413259982080000000, 3011361496339065143296, 206882551397716479442944, 14551915228366851806640625

Offset

0,3

Comments

See A374848 for the definition of obverse convolution and a guide to related sequences. If k>=0, then a(2k) is even and a(2k+1) is a square.

Links

Table of n, a(n) for n=0..17.

Formula

a(n) ~ exp(-1/3) * (3*n/2)^(n+1). - Vaclav Kotesovec, Aug 02 2024

Mathematica

s[n_] := Floor[3 n/2]; t[n_] := Floor[3 n/2];
u[n_] := Product[s[k] + t[n - k], {k, 0, n}]
Table[u[n], {n, 0, 24}]

Crossrefs

Cf. A016789, A374848.

Sequence in context: A157708 A159537 A136660 * A374862 A362808 A365137

Adjacent sequences: A374877 A374878 A374879 * A374881 A374882 A374883

Keyword

nonn

Author

Clark Kimberling, Jul 31 2024

Status

approved