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A304370
Number of function calls of the first kind required to compute ack(3,n), where ack denotes the Ackermann function.
3
9, 58, 283, 1244, 5213, 21342, 86367, 347488, 1394017, 5584226, 22353251, 89445732, 357848421, 1431524710, 5726360935, 22905967976, 91624920425, 366501778794, 1466011309419, 5864053626220, 23456231282029, 93824958682478, 375299901838703, 1501199741572464
OFFSET
0,1
COMMENTS
The distinction between different kinds of recursive calls is based on a naive implementation of the Ackermann function in C.
int ack(int m, int n)
{
// Final result
....if (m==0) return n + 1;
.
// Recursive calls of the first kind:
....if (n==0) return ack(m - 1, 1);
.
// Recursive calls of the second kind:
....return ack(m - 1, ack(m, n - 1));
}
FORMULA
G.f.: (8*x^2-14*x+9)/((4*x-1)*(2*x-1)*(x-1)^2). - Alois P. Heinz, May 12 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Olivier Gérard, May 11 2018
STATUS
approved