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

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:
   3;
   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