A046212 First numerator and then denominator of central elements of Leibniz's Harmonic Triangle.

1, 1, 1, 6, 1, 30, 1, 140, 1, 630, 1, 2772, 1, 12012, 1, 51480, 1, 218790, 1, 923780, 1, 3879876, 1, 16224936, 1, 67603900, 1, 280816200, 1, 1163381400, 1, 4808643120, 1, 19835652870, 1, 81676217700, 1, 335780006100, 1, 1378465288200, 1

Offset: 1

Author

Mohammad K. Azarian

Keywords

• nonn
• easy

References

• L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 83, Problem 25.

Crossrefs

Cf. A003506.

Cf. A002457.

Formula

a(2n+1) = A056040(2n+1) = A100071(2n+1). - M. F. Hasler, Jan 25 2012

Extensions

More terms from James Sellers, Dec 13 1999