A063132 Composite numbers not divisible by 2 or 3 which in base 3 contain their largest proper factor as a substring.

49, 427, 671, 949, 1387, 1679, 1849, 2117, 3397, 3829, 4307, 6017, 6169, 7141, 8299, 10547, 11773, 13703, 17161, 17819, 19517, 24523, 25019, 25877, 29941, 30607, 31459, 33853, 34447, 34547, 35657, 35947, 38243, 38491, 38579, 39283, 45571

Offset: 1

Author

Robert G. Wilson v, Aug 08 2001

Keywords

• base
• nonn

Crossrefs

Cf. A063127, A062238.

Programs

Mathematica

Do[ If[ !PrimeQ[ n ] && Mod[ n, 3 ] != 0 && StringPosition[ ToString[ FromDigits[ IntegerDigits[ n, 3 ] ] ], ToString[ FromDigits[ IntegerDigits[ Divisors[ n ][ [ -2 ] ], 3 ] ] ] ] != {}, Print[ n ] ], {n, 3, 10^5, 2} ]