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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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..37.

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} ]

CROSSREFS

Cf. A063127, A062238.

Sequence in context: A168572 A350382 A063874 * A250081 A250082 A012097

Adjacent sequences: A063129 A063130 A063131 * A063133 A063134 A063135

KEYWORD

base,nonn

AUTHOR

Robert G. Wilson v, Aug 08 2001

STATUS

approved