A136099 Triangle read by rows: the number of ways to factor 5*2^(n-k)*3^k, columns 0<=k<=n, rows n>=0.

1, 2, 2, 4, 5, 4, 7, 11, 11, 7, 12, 21, 26, 21, 12, 19, 38, 52, 52, 38, 19, 30, 64, 98, 109, 98, 64, 30, 45, 105, 171, 212, 212, 171, 105, 45, 67, 165, 289, 382, 424, 382, 289, 165, 67, 97, 254, 467, 662, 783, 783, 662, 467, 254, 97, 139, 381, 737, 1097, 1386, 1481, 1386, 1097, 737, 381, 139

Offset

0,2

Comments

Second in the series of arrays beginning with A054225.

Links

Table of n, a(n) for n=0..65.

Formula

T(n,k) = A001055(5*A036561(n,k)).

Example

5*A036561(2,1) = 5*6 = 30 and there are five ways to factor 30.
Triangle begins:
   1;
   2,  2;
   4,  5,  4;
   7, 11, 11,   7;
  12, 21, 26,  21, 12;
  19, 38, 52,  52, 38, 19;
  30, 64, 98, 109, 98, 64, 30;
  ...

Crossrefs

Cf. A001055, A036561, A054225, A129306, A131419.

Sequence in context: A284722 A202876 A128900 * A210597 A252836 A286101

Adjacent sequences: A136096 A136097 A136098 * A136100 A136101 A136102

Keyword

nonn,tabl

Author

Alford Arnold, Dec 15 2007

Status

approved