1,2
J. Riordan, The blossoming of Schroeder's fourth problem, Acta Math., 137 (1976), 1-16.
Triangle begins:
1
2 2
4 16 6
8 88 116 24
Sequence in context: A122598 A087783 A176190 * A153991 A153994 A102864
Adjacent sequences: A106238 A106239 A106240 * A106242 A106243 A106244
nonn,tabl
N. J. A. Sloane (njas(AT)research.att.com), May 29 2005