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A221531
Triangle read by rows: T(n,k) = A000005(n-k+1)*A000041(k-1), n>=1, k>=1.
15
1, 2, 1, 2, 2, 2, 3, 2, 4, 3, 2, 3, 4, 6, 5, 4, 2, 6, 6, 10, 7, 2, 4, 4, 9, 10, 14, 11, 4, 2, 8, 6, 15, 14, 22, 15, 3, 4, 4, 12, 10, 21, 22, 30, 22, 4, 3, 8, 6, 20, 14, 33, 30, 44, 30, 2, 4, 6, 12, 10, 28, 22, 45, 44, 60, 42, 6, 2, 8, 9, 20, 14, 44, 30, 66, 60, 84, 56
OFFSET
1,2
FORMULA
T(n,k) = d(n-k+1)*p(k-1), n>=1, k>=1.
EXAMPLE
For n = 6:
-------------------------
k A000041 T(6,k)
1 1 * 4 = 4
2 1 * 2 = 2
3 2 * 3 = 6
4 3 * 2 = 6
5 5 * 2 = 10
6 7 * 1 = 7
-------------------------
So row 6 is [4, 2, 6, 6, 10, 7]. Note that the sum of row 6 is 4+2+6+6+10+7 = 35 equals A006128(6).
.
Triangle begins:
1;
2, 1;
2, 2, 2;
3, 2, 4, 3;
2, 3, 4, 6, 5;
4, 2, 6, 6, 10, 7;
2, 4, 4, 9, 10, 14, 11;
4, 2, 8, 6, 15, 14, 22, 15;
3, 4, 4, 12, 10, 21, 22, 30, 22;
4, 3, 8, 6, 20, 14, 33, 30, 44, 30;
2, 4, 6, 12, 10, 28, 22, 45, 44, 60, 42;
6, 2, 8, 9, 20, 14, 44, 30, 66, 60, 84, 56;
...
CROSSREFS
Mirror of A221530. Columns 1-3: A000005, A000005, A062011. Leading diagonals 1-2: A000041, A139582. Row sums give A006128.
Sequence in context: A261679 A147657 A029232 * A282970 A025807 A120254
KEYWORD
nonn,tabl
AUTHOR
Omar E. Pol, Jan 19 2013
STATUS
approved