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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A014348 Three-fold exponential convolution of primes with themselves (divided by 2). 1
4, 18, 84, 393, 1830, 8433, 38376, 171957, 757362, 3271533, 13849980, 57396693, 233039058, 927277245, 3624209748, 13934877933, 52843565490, 197989340133, 734212702164, 2698456656933, 9837838481154, 35609804891973, 128026118332596, 457386991178451 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..1000

MAPLE

b:= proc(n, k) option remember; `if`(k=1, ithprime(n+1), add(

      b(j, floor(k/2))*b(n-j, ceil(k/2))*binomial(n, j), j=0..n))

    end:

a:= n-> b(n, 3)/2:

seq(a(n), n=0..30);  # Alois P. Heinz, Jun 07 2018

MATHEMATICA

b[n_, k_] := b[n, k] = If[k==1, Prime[n+1], Sum[b[j, Floor[k/2]] b[n-j, Ceiling[k/2]] Binomial[n, j], {j, 0, n}]];

a[n_] := b[n, 3]/2;

a /@ Range[0, 30] (* Jean-Fran├žois Alcover, Nov 16 2020, after Alois P. Heinz *)

CROSSREFS

Cf. A014347.

Sequence in context: A218986 A143646 A290916 * A126020 A086405 A151251

Adjacent sequences:  A014345 A014346 A014347 * A014349 A014350 A014351

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

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 October 21 00:18 EDT 2021. Contains 348119 sequences. (Running on oeis4.)