The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A161971 E.g.f. satisfies: A(x) = exp( x*exp( x*A'(x) ) ), where A'(x) = d/dx A(x). 1
 1, 1, 3, 28, 521, 15596, 672457, 39049396, 2919995969, 272314100944, 30921124212881, 4195725816103724, 670156359448985521, 124435720115244671056, 26578720273153614206201 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Vaclav Kotesovec, Table of n, a(n) for n = 0..230 FORMULA a(n) ~ c * n * (n!)^2, where c = 0.2773256592699... - Vaclav Kotesovec, Aug 24 2017 EXAMPLE E.g.f.: A(x) = 1 + x + 3*x^2/2! + 28*x^3/3! + 521*x^4/4! + 15596*x^5/5! +... exp(x*A'(x)) = 1 + x + 7*x^2/2! + 103*x^3/3! + 2565*x^4/4! + 94881*x^5/5! +... where log(A(x)) = x*exp(x*A'(x)): log(A(x)) = x + 2*x^2/2! + 21*x^3/3! + 412*x^4/4! + 12825*x^5/5! + 569286*x^6/6! +... PROG (PARI) {a(n)=local(A=1+x); for(i=1, n, A=exp(x*exp(x*deriv(A)+O(x^n)))); n!*polcoeff(A, n)} CROSSREFS Cf. A161967 (variant). Sequence in context: A180710 A005328 A192559 * A156315 A248571 A062497 Adjacent sequences:  A161968 A161969 A161970 * A161972 A161973 A161974 KEYWORD nonn AUTHOR Paul D. Hanna, Jun 23 2009 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 5 12:24 EST 2021. Contains 349557 sequences. (Running on oeis4.)