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Search: id:A118693
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| A118693 |
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Semiprimes which are divisible by the sum of their digits. |
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+0
2
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| 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; listen)
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OFFSET
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1,1
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EXAMPLE
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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.
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MATHEMATICA
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spQ[n_] := Plus @@ Last /@ FactorInteger@n == 2; Select[Range@7542, spQ@# && IntegerQ[ #/Plus @@ IntegerDigits@# ] &] - Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 10 2006
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CROSSREFS
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Cf. A001358, A118694.
Sequence in context: A135257 A118697 A118695 this_sequence A084668 A085842 A131220
Adjacent sequences: A118690 A118691 A118692 this_sequence A118694 A118695 A118696
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KEYWORD
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base,nonn
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AUTHOR
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Luc Stevens (lms022(AT)yahoo.com), May 20 2006
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 10 2006
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