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

Author

Clark Kimberling, Jul 31 2024

Keywords

• nonn

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.

Crossrefs

Cf. A016789, A374848.

Programs

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}]

Formula

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