A143273 Triangle read by rows: A127648 * A000012 * A130209.

1, 2, 4, 3, 6, 6, 4, 8, 8, 12, 5, 10, 10, 15, 10, 6, 12, 12, 18, 12, 24, 7, 14, 14, 21, 14, 28, 14, 8, 16, 16, 24, 16, 32, 16, 32, 9, 18, 18, 27, 18, 36, 18, 36, 27, 10, 20, 20, 30, 20, 40, 20, 40, 30, 40, 11, 22, 22, 33, 22, 44, 22, 44, 33, 44, 22

Offset

1,2

Comments

Row sums = A143274: (1, 6, 15, 32, 50, 84, ...).

Links

Table of n, a(n) for n=1..66.

Formula

T(n,k) = n*d(k).

Example

First few rows of the triangle =
  1;
  2,  4;
  3,  6,  6;
  4,  8,  8, 12;
  5, 10, 10, 15, 10;
  6, 12, 12, 18, 12, 24;
  7, 14, 14, 21, 14, 28, 14;
  8, 16, 16, 24, 16, 32, 16, 32;
  ...
T(6,3) = 12 = 6*d(3) = 6*2, where A000005 = d(k) = (1, 2, 3, 2, 2, 4, 2, 4, 3, ...).

Prog

(PARI) tabl(nn) = for (n=1, nn, for (k=1, n, print1(n*numdiv(k), ", "))); \\ Michel Marcus, Mar 19 2016

Crossrefs

Cf. A000005, A127648, A130209, A143274.

Sequence in context: A332450 A245454 A375615 * A141429 A309131 A162953

Adjacent sequences: A143270 A143271 A143272 * A143274 A143275 A143276

Keyword

nonn,tabl

Author

Gary W. Adamson, Aug 03 2008

Extensions

a(48) = 20 inserted by Georg Fischer, Jun 05 2023

Status

approved