login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A337597 a(0) = 1; a(n) = (1/n) * Sum_{k=1..n} binomial(n,k)^2 * k * 6^(k-1) * a(n-k). 6
1, 1, 8, 96, 1896, 55416, 2182752, 111162528, 7088997888, 550749341952, 51058009732608, 5556160183592448, 699989463219105792, 100917906076208203776, 16486415052067886690304, 3026039346413717945757696, 619431153899977856767131648, 140491838894751995366936641536, 35102748598142373142198776889344 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Robert Israel, Table of n, a(n) for n = 0..200

FORMULA

Sum_{n>=0} a(n) * x^n / (n!)^2 = exp((BesselI(0,2*sqrt(6*x)) - 1) / 6).

Sum_{n>=0} a(n) * x^n / (n!)^2 = exp(Sum_{n>=1} 6^(n-1) * x^n / (n!)^2).

MAPLE

S:= series(exp((BesselI(0, 2*sqrt(6*x))-1)/6), x, 51):

seq(coeff(S, x, j)*(j!)^2, j=0..50); # Robert Israel, Sep 06 2020

MATHEMATICA

a[0] = 1; a[n_] := a[n] = (1/n) Sum[Binomial[n, k]^2 k 6^(k - 1) a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 18}]

nmax = 18; CoefficientList[Series[Exp[(BesselI[0, 2 Sqrt[6 x]] - 1)/6], {x, 0, nmax}], x] Range[0, nmax]!^2

CROSSREFS

Cf. A005012, A337592, A337593, A337594, A337595.

Sequence in context: A002168 A114425 A224767 * A052127 A300474 A338571

Adjacent sequences:  A337594 A337595 A337596 * A337598 A337599 A337600

KEYWORD

nonn

AUTHOR

Ilya Gutkovskiy, Sep 02 2020

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 26 02:45 EDT 2022. Contains 354074 sequences. (Running on oeis4.)