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A118693 Semiprimes which are divisible by the sum of their digits. 2
4, 6, 9, 10, 21, 111, 133, 201, 209, 247, 407, 481, 511, 629, 803, 1011, 1101, 1141, 1387, 1417, 1651, 1679, 1853, 2119, 2159, 2353, 2771, 3031, 3077, 3097, 3383, 3439, 3523, 3749, 3781, 4577, 4607, 5149, 5161, 5219, 5833, 6331, 6443, 7033, 7361, 7501 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..46.

EXAMPLE

133 is in the sequence because (1) it is a semiprime, (2) the sum of its digits is 1+3+3=7 and (3) 133 is divisible by 7.

MATHEMATICA

spQ[n_] := Plus @@ Last /@ FactorInteger@n == 2; Select[Range@7542, spQ@# && IntegerQ[ #/Plus @@ IntegerDigits@# ] &] - Robert G. Wilson v, Jun 10 2006

CROSSREFS

Cf. A001358, A118694.

Sequence in context: A118695 A235108 A215478 * A084668 A085842 A131220

Adjacent sequences:  A118690 A118691 A118692 * A118694 A118695 A118696

KEYWORD

base,nonn

AUTHOR

Luc Stevens (lms022(AT)yahoo.com), May 20 2006

EXTENSIONS

More terms from Robert G. Wilson v, Jun 10 2006

STATUS

approved

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Last modified April 25 00:32 EDT 2017. Contains 285346 sequences.