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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
OFFSET
0,1
LINKS
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-François Alcover, Nov 16 2020, after Alois P. Heinz *)
CROSSREFS
Cf. A014347.
Sequence in context: A218986 A143646 A290916 * A126020 A086405 A151251
KEYWORD
nonn
AUTHOR
STATUS
approved