A140218 Denominators of the inverse triangle to that described in A133135.

1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 4, 1, 2, 1, 1, 4, 1, 2, 1, 1, 1, 4, 1, 1, 1, 2, 1, 1, 4, 1, 1, 1, 2, 1, 1, 1, 8, 1, 2, 1, 4, 1, 2, 1, 1, 8, 1, 2, 1, 4, 1, 2, 1, 1, 1, 8, 1, 1, 1, 4, 1, 2, 1, 2, 1, 1, 8, 1, 1, 1, 4, 1, 2, 1, 2, 1, 1, 1, 8, 1, 2, 1, 2, 1, 2, 1, 4, 1, 2, 1, 1, 8, 1, 2, 1, 2, 1, 2, 1, 4, 1, 2, 1, 1

Offset

0,5

Comments

The inverse of the triangle of fractions starts

1;

-1, 1;

1, -3/2, 1;

-1, 3/2,-2, 1;

1, -5/4, 2, -5/2, 1;

-1, 5/4 -1, 5/2, -3, 1;

1, -7/4, 1, 0, 3, -7/2, 1;

-1, 7/4,-4, 0, 2, 7/2,-4, 1;

1, 3/8, 4,-21/2, -2, 21/4, 4,-9/2, 1;

-1, -3/8,13, 21/2,-26,-21/4,10, 9/2,-5, 1;

to yield the triangle of denominators

1;

1,1;

1,2,1;

1,2,1,1;

1,4,1,2,1;

1,4,1,2,1,1;

1,4,1,1,1,2,1;

1,4,1,1,1,2,1,1;

1,8,1,2,1,4,1,2,1;

1,8,1,2,1,4,1,2,1,1;

1,8,1,1,1,4,1,2,1,2,1;

1,8,1,1,1,4,1,2,1,2,1,1;

Number pairs show up if reading this along diagonals or columns.

Links

Table of n, a(n) for n=0..104.

Crossrefs

Cf. A133135, A140216, A000079.

Sequence in context: A117975 A143258 A027199 * A193805 A159704 A348194

Adjacent sequences: A140215 A140216 A140217 * A140219 A140220 A140221

Keyword

nonn,frac,tabl

Author

Paul Curtz, Jun 22 2008

Extensions

Extended by R. J. Mathar, Aug 02 2008

Status

approved