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 A371407 Expansion of (1/x) * Series_Reversion( x / ( (1+x)^2 * (1+3*x)^2 ) ). 0
 1, 8, 86, 1064, 14289, 202488, 2980380, 45122792, 698214548, 10993069856, 175546104958, 2836384141720, 46285381498750, 761735217877200, 12628402069223160, 210704642400488040, 3535494883741420908, 59621314428576557664, 1009942893735988354296 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Table of n, a(n) for n=0..18. Index entries for reversions of series FORMULA a(n) = (1/(n+1)) * Sum_{k=0..n} 3^k * binomial(2*(n+1),k) * binomial(2*(n+1),n-k). PROG (PARI) my(N=20, x='x+O('x^N)); Vec(serreverse(x/((1+x)^2*(1+3*x)^2))/x) (PARI) a(n) = sum(k=0, n, 3^k*binomial(2*(n+1), k)*binomial(2*(n+1), n-k))/(n+1); CROSSREFS Cf. A002293, A371406. Sequence in context: A180582 A230621 A357420 * A369505 A268052 A268075 Adjacent sequences: A371404 A371405 A371406 * A371408 A371409 A371410 KEYWORD nonn AUTHOR Seiichi Manyama, Mar 21 2024 STATUS approved

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Last modified September 7 19:14 EDT 2024. Contains 375749 sequences. (Running on oeis4.)