A046205 In Leibniz's Harmonic Triangle, write numerator first and then denominator of each element.

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, 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

Offset

1,4

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, A046206, A046212, A046201, A046204, A046208, A007622, A137752, A137753, A137754.

Sequence in context: A271825 A271875 A324194 * A046206 A137753 A134780

Adjacent sequences: A046202 A046203 A046204 * A046206 A046207 A046208

Keyword

tabf,nonn,easy,less

Author

Mohammad K. Azarian

Extensions

More terms from Gregory D Johnson (gjohn(AT)iname.com)

Edited by M. F. Hasler, Apr 05 2015

Status

approved