login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A277362 Self-convolution of a(n)/4^n gives factorials (A000142). 1
1, 2, 14, 164, 2646, 53852, 1316364, 37467080, 1215510118, 44249471916, 1785942489700, 79150848980216, 3821494523507708, 199668288426274968, 11225643465179779544, 675769562728962818448, 43370783734391689628294, 2956329387192674856638668 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Self-convolution of a(n) gives A047053.

LINKS

Table of n, a(n) for n=0..17.

FORMULA

Sum_{k=0..n} a(k)/4^k * a(n-k)/4^(n-k) = n!.

MAPLE

a:= proc(n) option remember; `if`(n=0, 1,

     (n!*4^n-add(a(k)*a(n-k), k=1..n-1))/2)

    end:

seq(a(n), n=0...20);  # Alois P. Heinz, Oct 12 2016

MATHEMATICA

With[{n = 20}, Sqrt[Sum[k! (4 x)^k, {k, 0, n - 1}] + O[x]^n][[3]]]

CROSSREFS

Cf. A000142, A000302, A047053.

Sequence in context: A074635 A201465 A245894 * A209937 A245896 A124215

Adjacent sequences:  A277359 A277360 A277361 * A277363 A277364 A277365

KEYWORD

nonn

AUTHOR

Vladimir Reshetnikov, Oct 10 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified February 21 00:50 EST 2018. Contains 299388 sequences. (Running on oeis4.)