A316140 - OEIS

A316140

Denominator of the autosequence 2/((n+2)*(n+3)) difference table written by antidiagonals.

3, 6, 6, 10, 15, 10, 15, 30, 30, 15, 21, 105, 70, 105, 21, 28, 84, 140, 140, 84, 28, 36, 126, 252, 315, 252, 126, 36, 45, 180, 420, 630, 630, 420, 180, 45, 55, 495, 660, 1155, 1386, 1155, 660, 495, 55, 66, 330

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

0,1

LINKS

Table of n, a(n) for n=0..46.

OEIS Wiki, Autosequence

EXAMPLE

Difference table:

1/3, 1/6, 1/10, 1/15, ...

-1/6, -1/15, -1/30, -2/105, ...

1/10, 1/30, 1/70, 1/140, ...

-1/15, -2/105, -1/140, -1/315, ... .

...

Table starts:

3 6 10 15 21 28 ...

6 15 30 105 84 126 ...

10 30 70 140 252 420 ...

15 105 140 315 630 1155 ...

21 84 252 630 1386 2772 ...

...

As a triangle:

6, 6;

10, 15, 10;

15, 30, 30, 15;

...

PROG

(PARI) tabl(nn) = {nn = 2*nn; m = matrix(nn, nn, n, k, if (n==1, 2/((k+1)*(k+2)))); for (n=2, nn, for (k=1, nn-n +1, m[n, k] = m[n-1, k+1] - m[n-1, k]; ); ); nn = nn/2; matrix(nn, nn, n, k, denominator(m[n, k])); } \\ Michel Marcus, Jul 05 2018

CROSSREFS

Cf. A000217, A003506, A033876? (main diagonal), A059481, A109613.

Sequence in context: A333616 A316563 A349212 * A147849 A332546 A002853

Adjacent sequences: A316137 A316138 A316139 * A316141 A316142 A316143

KEYWORD

nonn,frac,tabl,more

AUTHOR

Paul Curtz, Jun 25 2018

STATUS

approved