A247683 Odd composite numbers congruent to 7 modulo 9.

25, 115, 133, 169, 187, 205, 259, 295, 385, 403, 475, 493, 511, 529, 565, 583, 637, 655, 745, 763, 781, 799, 817, 835, 871, 889, 925, 943, 961, 979, 1015, 1105, 1141, 1159, 1177, 1195, 1267, 1285, 1339, 1357, 1375, 1393, 1411, 1465, 1501

Offset: 1

Author

Odimar Fabeny, Sep 22 2014

Keywords

• nonn
• easy

Comments

Subsequence of A017245 (9n + 7).

Links

• Odimar Fabeny, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A017245, A247676, A247678, A247679, A247681, A247682.

Programs

Mathematica

Select[18Range[100] + 7, Not[PrimeQ[#]] &] (* Alonso del Arte, Sep 25 2014 *)
Select[Range[1,1501,2],CompositeQ[#]&&Mod[#,9]==7&] (* or *) Select[Range[7,1501,18],CompositeQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 31 2021 *)

PARI

lista(nn) = {forcomposite(n=1, nn, if ((n % 2) && ((n % 9) == 7), print1(n, ", ")); ); } \\ Michel Marcus, Sep 22 2014