# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a143602 Showing 1-1 of 1 %I A143602 #2 Mar 30 2012 18:37:12 %S A143602 1,1,1,7,-11,741,-14129,521263,-20968359,1063764649,-63316356389, %T A143602 4408796480331,-352958649497387,32158017135672013, %U A143602 -3302679619545572265,379346145007147112551,-48397471256028983134799,6817654800019973404119633,-1054828080584161260522077645 %N A143602 E.g.f. satisfies: A(x) = exp( A(x)*Series_Reversion[x*A(x)] ). %F A143602 E.g.f. satisfies: A(x*A(x)) = exp(x*A(x*A(x))) = LambertW(-x)/(-x). %e A143602 A(x) = 1 + x + x^2/2! + 7*x^3/3! - 11*x^4/4! + 741*x^5/5! - 14129*x^6/6! +-... %e A143602 A(x*A(x)) = 1 + x + 3*x^2/2! + 16*x^3/3! + 125*x^4/4! + 1296*x^5/5! +... %e A143602 LambertW(-x)/(-x) = 1 + x + 3^1*x^2/2! + 4^2*x^3/3! + 5^3*x^4/4! +... %e A143602 log(A(x)) = x + 2*x^3/2! - 9*x^4/3! + 172*x^5/4! - 3205*x^6/5! +-... %e A143602 Series_Reversion[x*A(x)] = x - x^2 + 3*x^3/2! - 22*x^4/3! + 281*x^5/4! - 5396*x^6/5! +-... %o A143602 (PARI) {a(n)=local(A=1);for(i=0,n,A=exp(A*serreverse(x*A+x^2*O(x^n))));n!*polcoeff(A,n)} %Y A143602 Cf. A000272. %K A143602 sign %O A143602 0,4 %A A143602 _Paul D. Hanna_, Aug 26 2008 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE