Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.

0,5

It appears that the T(n,k) are always integers. This would follow from the conjectured prime factorization given in the comments section of A092143.

Table of n, a(n) for n=0..64.

T(n,k) = product_{j=1..n} floor(n/j)!/((product_{j=1..n-k} floor((n-k)/j)!)*(product_{j=1..k} floor(k/j)!)).

Triangle starts

1

1 1

1 2 1

1 3 3 1

1 8 12 8 1

1 5 20 20 5 1

Second column T(n, 1) is A007955, A092143.

Sequence in context: A215292 A124975 A171246 * A176469 A141542 A129453

Adjacent sequences: A129436 A129437 A129438 * A129440 A129441 A129442

easy,nonn,tabl

Peter Bala, Apr 15 2007

approved