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The Hankel transform of this sequence is 3^n (see A000244) .
Table of n, a(n) for n=0..22.
Conjecture: 2*n*a(n) +(-19*n+12)*a(n-1) +6*(8*n-11)*a(n-2) +36*(-n+2)*a(n-3)=0. - R. J. Mathar, Jun 30 2013
Row sums of triangle in A124575 .
Sequence in context: A263667 A101106 A165310 * A194089 A178807 A047891
Adjacent sequences: A133155 A133156 A133157 * A133159 A133160 A133161
Philippe Deléham, Oct 08 2007