login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A304370 Number of function calls of the first kind required to compute ack(3,n), where ack denotes the Ackermann function. 2
9, 58, 283, 1244, 5213, 21342, 86367, 347488, 1394017, 5584226, 22353251, 89445732, 357848421, 1431524710, 5726360935, 22905967976, 91624920425, 366501778794, 1466011309419, 5864053626220, 23456231282029, 93824958682478, 375299901838703, 1501199741572464 (list; graph; refs; listen; history; text; internal format)
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));

}

LINKS

Table of n, a(n) for n=0..23.

Index entries for linear recurrences with constant coefficients, signature (8,-21,22,-8).

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

Cf. A036563, A074877, A304371.

Sequence in context: A044147 A044528 A027174 * A099624 A018218 A026750

Adjacent sequences:  A304367 A304368 A304369 * A304371 A304372 A304373

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard, May 11 2018

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 16 16:13 EDT 2019. Contains 328101 sequences. (Running on oeis4.)