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A158841
Triangle read by rows, matrix product of A145677 * A004736.
2
1, 3, 1, 7, 4, 2, 13, 9, 6, 3, 21, 16, 12, 8, 4, 31, 25, 20, 15, 10, 5, 43, 36, 30, 24, 18, 12, 6, 57, 49, 42, 35, 28, 21, 14, 7, 73, 64, 56, 48, 40, 32, 24, 16, 8, 91, 81, 72, 63, 54, 45, 36, 27, 18, 9
OFFSET
1,2
FORMULA
T(n,k) = Sum_{j=k..n} A145677(n-1,j-1)*A004736(j,k), assuming column enumeration k >= 1 in A004736. - R. J. Mathar, Nov 05 2011
EXAMPLE
First few rows of the triangle:
1;
3, 1;
7, 4, 2;
13, 9, 6, 3;
21, 16, 12, 8, 4;
31, 25, 20, 15, 10, 5;
43, 36, 30, 24, 18, 12, 6;
57, 49, 42, 35, 28, 21, 14, 7;
73, 64, 56, 48, 40, 32, 24, 16, 8;
91, 81, 72, 63, 54, 45, 36, 27, 18, 9;
111, 100, 90, 80, 70, 60, 50, 40, 30, 20, 10;
133, 121, 110, 99, 88, 77, 66, 55, 44, 33, 22, 11;
157, 144, 132, 120, 108, 96, 84, 72, 60, 48, 36, 24, 12;
...
MAPLE
A145677 := proc(n, k)
if n <0 or k < 0 or k > n then
0;
elif k = 0 then
1;
elif k = n then
n ;
else
0 ;
end if;
end proc:
A004736 := proc(n, k)
if n <0 or k < 1 or k > n then
0;
else
n-k+1 ;
end if;
end proc:
A158841 := proc(n, k)
add( A145677(n-1, j-1)*A004736(j, k), j=k..n) ;
end proc: # R. J. Mathar, Nov 05 2011
CROSSREFS
Cf. A145677, A002061 (column k=1), A158842 (row sums).
Sequence in context: A286513 A193970 A274510 * A213576 A021319 A190177
KEYWORD
nonn,tabl,easy
AUTHOR
STATUS
approved