A373899 Semiprimes q*p such that q^p == p (mod (q - p)), where q > p.

6, 15, 21, 33, 35, 55, 65, 77, 85, 91, 133, 143, 145, 155, 161, 187, 209, 217, 221, 247, 253, 265, 299, 301, 323, 341, 377, 391, 403, 415, 437, 451, 481, 493, 533, 545, 551, 553, 559, 581, 589, 611, 629, 667, 671, 689, 697, 703, 713, 781, 793, 799, 817, 893, 899, 901

Offset

1,1

Links

Table of n, a(n) for n=1..56.

Example

15 = 3*5 is a term because 5^3 == 3 (mod 2).

Mathematica

seqQ[n_] := Module[{f = FactorInteger[n], p, q}, If[f[[;; , 2]] == {1, 1}, p = f[[1, 1]]; q = f[[2, 1]]; PowerMod[q, p, q - p] == Mod[p, q - p], False]]; Select[Range[1000], seqQ] (* Amiram Eldar, Jun 26 2024 *)

Crossrefs

Subsequence of A001358.

Cf. A037074 (subsequence), A046388, A371811.

Sequence in context: A330205 A015793 A393644 * A261078 A063466 A377713

Adjacent sequences: A373896 A373897 A373898 * A373900 A373901 A373902

Keyword

nonn

Author

Juri-Stepan Gerasimov, Jun 22 2024

Status

approved