A137762 Central elements in writing first the numerator and then the denominator (left to right) of Leibniz's harmonic-like triangle.

1, 1, 5, 6, 31, 30, 209, 140, 1471, 630, 10625, 2772

Offset

1,3

Links

Table of n, a(n) for n=1..12.

Formula

From M. F. Hasler, Jan 25 2012: (Start)

a(2*n-1) = A137763(2*n).

a(2*n) = A137763(2*n-1) = A046212(2*n-1) = A056040(2*n-1) = A100071(2*n-1). (End)

Example

1/1; --> 1 1
1/2, 1/2; -->
1/3, 5/6, 1/3; --> 5 6
1/4, 7/12, 7/12, 1/4; --> ...
1/5, 9/20, 31/30, 9/20, 1/5;

Crossrefs

Cf. A003506, A046201, A046204, A046205, A046206, A046208, A046212, A137752, A137753, A137754, A137755, A137756, A137757, A137758, A137759, A137760, A137761.

Sequence in context: A042643 A047179 A166023 * A177118 A151506 A122008

Adjacent sequences: A137759 A137760 A137761 * A137763 A137764 A137765

Keyword

nonn,tabf,frac,more

Author

Mohammad K. Azarian, Feb 13 2008

Status

approved