A059420 A diagonal of A059419.

1, 20, 616, 28160, 1805056, 154918400, 17171485696, 2389096202240, 407776690241536, 83793407533383680, 20407552701432856576, 5813146553630295326720, 1914890082050142493474816, 722310365729129175040655360, 309331648183856602708764000256

Offset: 0

Author

N. J. A. Sloane, Jan 30 2001

Keywords

• nonn
• easy

References

• L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 259.

Crossrefs

Cf. A059419, A060056, A060057.

Programs

PARI

a059419(n, k) = n!*polcoef(tan(x+x*O(x^n))^k/k!, n);
a(n) = a059419(2*n+3, 3); \\ Seiichi Manyama, May 11 2025

Formula

a(n) = A059419(2*n+3, 3). From the expansion of tan(x)^3/6.

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Feb 08 2001. Corrected and extended by Wolfdieter Lang, Feb 09 2001.

Offset changed to 0 by Seiichi Manyama, May 11 2025