A102046 Smallest positive integer greater than a(n - 1) consistent with the condition that n is a member of the sequence if and only if a(n) is congruent to (n!)!.

1, 1, 2, 6, 7, 8, 720, 721, 722, 723, 724, 726, 727, 728, 729, 780, 781, 782, 783, 784, 785, 786, 787, 789, 790, 791, 792, 793, 794, 795, 796, 797, 798, 799, 780, 781, 782, 783, 784, 785, 786, 787, 788, 789, 790, 791, 792, 793, 794, 795, 796, 797, 798, 799

Offset

0,3

Comments

The sequence is related to the fake even and fake odd sequences and also the factorial and double factorial sequences, so seems in the short run linear but in the long run exponential.

Links

Table of n, a(n) for n=0..53.

Formula

a(a(n)) = (n!)!

Example

a(6) = 720 because (3!)! = 6! = 720

Crossrefs

Cf. A080591, A080588, A000197, A000142.

Sequence in context: A261691 A351088 A296443 * A019913 A299421 A327181

Adjacent sequences: A102043 A102044 A102045 * A102047 A102048 A102049

Keyword

easy,nonn,obsc

Author

Michael Joseph Halm, Feb 12 2005

Extensions

The definition does not match the data. How was this sequence generated? - N. J. A. Sloane, Feb 21 2021

Status

approved