0,3

J.-M. Sixdeniers, K. A. Penson and A. I. Solomon, Extended Bell and Stirling Numbers From Hypergeometric Exponentiation, J. Integer Seqs. Vol. 4 (2001), #01.1.4.

a(n) = Sum_{pi} n!/(k(1)! * 1!^k(1) * k(2)! * 2!^k(2) * ... * k(n)! * n!^k(n)) * (n!/(1!^k(1) * 2!^k(2) * ... * n!^k(n)))^L, where pi runs through all partitions k(1) + 2 * k( 2) + ... + n * k(n) = n, with L = 3.

Sequence in context: A129934 A003303 A012838 this_sequence A104775 A106663 A135609

Adjacent sequences: A061682 A061683 A061684 this_sequence A061686 A061687 A061688

nonn

njas, Jun 18 2001

Formula and more terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Dec 09 2001