cp's OEIS Frontend

A272649 Compressed discriminator of the factorial numbers.

%I A272649 #27 Mar 07 2021 00:58:52
%S A272649 1,2,3,7,10,13,31,37,61,83,127,179,193,277,383,479,541,641,877,1013,
%T A272649 1423,2251,2339,2557,2663,3083,3301,5693,6229,9091,9377,17107,25447,
%U A272649 31193,39233,40879,46309,61471,72089,81707,86111,91243,116329,136207,149459,163729
%N A272649 Compressed discriminator of the factorial numbers.
%C A272649 The discriminator of the factorials is A208494 (replacing a(1) with 1), and the compressed discriminator is defined by reducing blocks of equal/repeated terms to a single instance. Because the discriminator is a monotonically increasing sequence, the compressed discriminator is just the records transform of the discriminator. - _R. J. Mathar_, May 11 2016
%D A272649 Olivier Gérard, Posting to Sequence Fans Mailing List, May 08 2016.
%H A272649 Arnold, L. K.; Benkoski, S. J.; and McCabe, B. J.; <a href="http://www.jstor.org/stable/2323651">The discriminator (a simple application of Bertrand's postulate)</a>. Amer. Math. Monthly 92 (1985), 275-277.
%H A272649 Sajed Haque and Jeffrey Shallit, <a href="http://arxiv.org/abs/1605.00092">Discriminators and k-Regular Sequences</a>, arXiv:1605.00092 [cs.DM], 2016.
%t A272649 R[n_, i_] := Union[Table[Mod[k!, i], {k, 1, n}]];
%t A272649 Reap[i0 = 1; Print[1]; Sow[1]; Do[Do[If[Length[R[n, i]] == n, If[i != i0, Print[i]; Sow[i]; i0 = i]; Goto[aa]], {i, 2, Max[n^2, 2]}]; Label[aa]; Continue, {n, 1, 10^4}] ][[2, 1]] (* _Jean-François Alcover_, Sep 14 2018, after _Zhi-Wei Sun_ in A208494 *)
%Y A272649 Cf. A000142, A208494.
%K A272649 nonn
%O A272649 1,2
%A A272649 _N. J. A. Sloane_, May 10 2016
%E A272649 a(32)-a(46) from _Alois P. Heinz_, May 11 2016