Search: id:A006230 Results 1-1 of 1 results found. %I A006230 M4902 %S A006230 1,13,73,301,1081,3613,11593,36301,111961,342013,1038313,3139501, %T A006230 9467641,28501213,85700233,257493901,773268121,2321377213,6967277353,20908123501 %N A006230 Bitriangular permutations. %D A006230 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %D A006230 S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. %D A006230 I. Kaplansky and J. Riordan, The problem of the rooks and its applications, Duke Math. J., 13 (1946), 259-268. %H A006230 S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. %H A006230 S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. %F A006230 a(n) = 12*S(n-2) + 1, with S(n)=A000392(n) the Stirling numbers of second kind. - Ralf Stephan (ralf(AT)ark.in-berlin.de), Jul 07 2003 %p A006230 A006230:=-(z+1)*(6*z+1)/(z-1)/(3*z-1)/(2*z-1); [Conjectured by S. Plouffe in his 1992 dissertation.] %Y A006230 Sequence in context: A081586 A143008 A107963 this_sequence A066110 A020527 A146618 %Y A006230 Adjacent sequences: A006227 A006228 A006229 this_sequence A006231 A006232 A006233 %K A006230 nonn %O A006230 4,2 %A A006230 N. J. A. Sloane (njas(AT)research.att.com). Search completed in 0.001 seconds