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 A156361 a(2n+2)=7*a(2n+1), a(2n+1)=7*a(2n)-6^n*A000108(n), a(0)=1. 6
 1, 6, 42, 288, 2016, 14040, 98280, 686880, 4808160, 33638976, 235472832, 1647983232, 11535882624, 80745019776, 565215138432, 3956385876480, 27694701135360, 193860506096640, 1357023542676480, 9499115800977408 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Hankel transform is 6^C(n+1,2). LINKS P. Barry, A Note on a One-Parameter Family of Catalan-Like Numbers, JIS 12 (2009) 09.5.4 FORMULA a(n)=sum{k=0..n, A120730(n,k)*6^k}. Conjecture: (n+1)*a(n) +7*(-n-1)*a(n-1) +24*(-n+2)*a(n-2) +168*(n-2)*a(n-3)=0. - R. J. Mathar, Jul 21 2016 MAPLE A156361 := proc(n)     option remember;     local nh;     if n= 0 then         1;     elif  type(n, 'even') then         7*procname(n-1);     else         nh := floor(n/2) ;         7*procname(n-1)-6^nh*A000108(nh) ;     end if; end proc: # R. J. Mathar, Jul 21 2016 CROSSREFS Cf. A000108, A156128, A001405, A151281, A151162, A151254, A156195 Sequence in context: A157335 A057089 A110711 * A216517 A055272 A155196 Adjacent sequences:  A156358 A156359 A156360 * A156362 A156363 A156364 KEYWORD nonn AUTHOR Philippe Deléham, Feb 08 2009 STATUS approved

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Last modified November 29 02:34 EST 2020. Contains 338756 sequences. (Running on oeis4.)