A046206 In Leibniz's Harmonic Triangle, write denominator first and then numerator of each element.

1, 1, 2, 1, 2, 1, 3, 1, 6, 1, 3, 1, 4, 1, 12, 1, 12, 1, 4, 1, 5, 1, 20, 1, 30, 1, 20, 1, 5, 1, 6, 1, 30, 1, 60, 1, 60, 1, 30, 1, 6, 1, 7, 1, 42, 1, 105, 1, 140, 1, 105, 1, 42, 1, 7, 1, 8, 1, 56, 1, 168, 1, 280, 1, 280, 1, 168, 1, 56, 1, 8, 1, 9, 1, 72, 1, 252, 1, 504, 1, 630, 1, 504, 1, 252

Offset

1,3

References

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

Links

Table of n, a(n) for n=1..85.

Example

1/1; 1/2, 1/2; 1/3, 1/6, 1/3; 1/4, 1/12, 1/12, 1/4; 1/5, 1/20, 1/30, 1/20, 1/5; ...

Crossrefs

Cf. A003506.

Sequence in context: A271875 A324194 A046205 * A137753 A134780 A247379

Adjacent sequences: A046203 A046204 A046205 * A046207 A046208 A046209

Keyword

tabf,nonn,easy

Author

Mohammad K. Azarian

Extensions

More terms from James A. Sellers, Dec 13 1999

Status

approved