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

 

Logo

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!)
A274738 E.g.f. satisfies: A(x) = exp( x * Integral A(x) dx ). 2
1, 2, 20, 480, 21200, 1495040, 154090560, 21851648000, 4080788691200, 970763776819200, 286589492301132800, 102814798964090470400, 44054406432402362880000, 22221550008574568038400000, 13033785372897433673984000000, 8796017673121387398310133760000, 6767531687276918248610686607360000, 5888477519317946191613742861516800000, 5753199370152454677482310592627507200000, 6271818135933778813784553455691078041600000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Since the e.g.f. is an even function, this sequence consists of the coefficients of only the even powers of x.

LINKS

Paul D. Hanna, Table of n, a(n) for n = 0..200

FORMULA

E.g.f. A(x) equals the logarithmic derivative of the e.g.f. of A274739.

a(n) ~ c * n!^2 * d^n / sqrt(n), where d = 3.0991310195... and c = 0.8742487... . - Vaclav Kotesovec, Jul 06 2016

EXAMPLE

E.g.f.: A(x) = 1 + 2*x^2/2! + 20*x^4/4! + 480*x^6/6! + 21200*x^8/8! + 1495040*x^10/10! + 154090560*x^12/12! + 21851648000*x^14/14! + 4080788691200*x^16/16! +...

where A(x) = exp( x * Integral A(x) dx ).

PROG

(PARI) {a(n) = my(A=1); for(i=0, n, A = exp( x*intformal( A +x*O(x^(2*n)) ) ) ); (2*n)!*polcoeff(A, 2*n)}

for(n=0, 20, print1(a(n), ", "))

CROSSREFS

Cf. A274739.

Sequence in context: A210901 A274572 A292396 * A012816 A012340 A279839

Adjacent sequences:  A274735 A274736 A274737 * A274739 A274740 A274741

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Jul 05 2016

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 2 05:01 EST 2021. Contains 349437 sequences. (Running on oeis4.)