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 A158196 Expansion of (1-x^2*c(x)^4)/(1-3*x*c(x)^2), c(x) the g.f. of A000108. 1
 1, 3, 14, 71, 370, 1950, 10332, 54895, 292106, 1555706, 8289732, 44186710, 235575028, 1256093084, 6698073528, 35719158591, 190488112122, 1015885525794, 5417869631028, 28894620083346, 154102115782812 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Apply the inverse of the Riordan array (1/(1-x^2),x/(1+x)^2) to 3^n. Hankel transform is A001653. LINKS FORMULA Conjecture: +3*(n+1)*a(n) +2*(-26*n+7)*a(n-1) +16*(18*n-25)*a(n-2) +256*(-2*n+5)*a(n-3)=0. - R. J. Mathar, Feb 05 2015 Conjecture: 3*(2*n+3)*(n+1)*a(n) +2*(-28*n^2-52*n+21)*a(n-1) +32*(2*n+5)*(2*n-3)*a(n-2)=0. - R. J. Mathar, Feb 05 2015 CROSSREFS Cf. A090317. Sequence in context: A186765 A109792 A137177 * A191649 A009637 A098648 Adjacent sequences:  A158193 A158194 A158195 * A158197 A158198 A158199 KEYWORD easy,nonn AUTHOR Paul Barry, Mar 13 2009 STATUS approved

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Last modified February 19 19:06 EST 2020. Contains 332047 sequences. (Running on oeis4.)