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 A158827 The 4th iteration of x*C(x) where C(x) is the Catalan function (A000108). 4
 1, 4, 20, 110, 640, 3870, 24084, 153306, 993978, 6544242, 43652340, 294469974, 2006018748, 13784115468, 95444016984, 665407010349, 4667570034444, 32922870719664, 233389493503968, 1662048903052380, 11885333877149532 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..21. Elżbieta Liszewska, Wojciech Młotkowski, Some relatives of the Catalan sequence, arXiv:1907.10725 [math.CO], 2019. FORMULA Series reversion of 1 -4*x +12*x^2 -30*x^3 +64*x^4 -118*x^5 +188*x^6 -258*x^7 +302*x^8 -298*x^9 +244*x^10 -162*x^11 +84*x^12 -32*x^13 +8*x^14 -x^15. - R. J. Mathar, Aug 30 2021 PROG (PARI) {a(n)=local(F=serreverse(x-x^2+O(x^(n+1))), G=x); for(i=1, 4, G=subst(F, x, G)); polcoeff(G, n)} CROSSREFS Cf. A158825, A158826, A158828, A158829. Sequence in context: A271932 A153295 A006770 * A263854 A026156 A025183 Adjacent sequences: A158824 A158825 A158826 * A158828 A158829 A158830 KEYWORD nonn AUTHOR Paul D. Hanna, Mar 28 2009 STATUS approved

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Last modified September 18 08:33 EDT 2024. Contains 375997 sequences. (Running on oeis4.)