A179444 Composite numbers m of the form m = 10k + 1 where k is also composite.

81, 91, 121, 141, 161, 201, 221, 261, 301, 321, 341, 351, 361, 381, 391, 441, 451, 481, 501, 511, 551, 561, 581, 621, 651, 681, 721, 741, 771, 781, 801, 841, 851, 861, 871, 901, 921, 931, 951, 961, 981, 1001, 1041, 1081, 1101, 1111, 1121, 1141, 1161, 1191, 1211, 1221, 1241, 1251, 1261, 1281, 1331

Offset

1,1

Comments

Corresponding values of k in A179443.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

select(t -> not isprime((t-1)/10) and not isprime(t), [seq(i, i=21..10001, 10)]); # Robert Israel, Jun 11 2019

Mathematica

Select[10#+1&/@Select[Range[100], !PrimeQ[#]&], !PrimeQ[#]&] (* Harvey P. Dale, Dec 01 2013 *)

Crossrefs

Sequence in context: A162529 A243260 A335066 * A068834 A067521 A117686

Adjacent sequences: A179441 A179442 A179443 * A179445 A179446 A179447

Keyword

nonn

Author

Jaroslav Krizek, Jul 14 2010

Extensions

More terms from Robert Israel, Jun 11 2019

Status

approved