cp's OEIS Frontend

A304370 Number of function calls of the first kind required to compute ack(3,n), where ack denotes the Ackermann function.

%I A304370 #12 May 13 2018 08:53:29
%S A304370 9,58,283,1244,5213,21342,86367,347488,1394017,5584226,22353251,
%T A304370 89445732,357848421,1431524710,5726360935,22905967976,91624920425,
%U A304370 366501778794,1466011309419,5864053626220,23456231282029,93824958682478,375299901838703,1501199741572464
%N A304370 Number of function calls of the first kind required to compute ack(3,n), where ack denotes the Ackermann function.
%C A304370 The distinction between different kinds of recursive calls is based on a naive implementation of the Ackermann function in C.
%C A304370 int ack(int m, int n)
%C A304370 {
%C A304370 // Final result
%C A304370 ....if (m==0) return n + 1;
%C A304370 .
%C A304370 // Recursive calls of the first kind:
%C A304370 ....if (n==0) return ack(m - 1, 1);
%C A304370 .
%C A304370 // Recursive calls of the second kind:
%C A304370 ....return ack(m - 1, ack(m, n - 1));
%C A304370 }
%H A304370 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (8,-21,22,-8).
%F A304370 G.f.: (8*x^2-14*x+9)/((4*x-1)*(2*x-1)*(x-1)^2). - _Alois P. Heinz_, May 12 2018
%Y A304370 Cf. A036563, A074877, A304371.
%K A304370 nonn,easy
%O A304370 0,1
%A A304370 _Olivier Gérard_, May 11 2018