A054769 Number of integer n-tuples {x(1),x(2),...,x(n)} with the following properties: (1) x(1)=1 and, for k>1, if d=x(k)-x(k-1), then (2) d is relatively prime to x(k-1) and (3) d=x(i) for some i in {1,2,...,k-1}.

1, 1, 1, 2, 5, 17, 67, 324, 1777, 11054, 76793, 591905, 4987228, 45712331, 452511382, 4812134735

Offset

1,4

Links

Table of n, a(n) for n=1..16.

Sean A. Irvine, Java program (github)

Crossrefs

Sequence in context: A122206 A104082 A166474 * A003510 A051625 A056098

Adjacent sequences: A054766 A054767 A054768 * A054770 A054771 A054772

Keyword

nonn,more

Author

John W. Layman, May 18 2000

Extensions

a(13)-a(16) from Sean A. Irvine, Feb 23 2022

Status

approved