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Search: id:A118559
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| A118559 |
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Lucky numbers for which both the sum of the digits and the product of the digits is also a lucky number. |
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+0
1
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| 1, 3, 7, 9, 111, 133, 135, 171, 331, 357, 535, 537, 553, 717, 735, 11113, 11137, 11173, 11371, 11373, 11535, 11731, 11911, 13113, 13117, 13179, 13317, 13335, 13371, 13515, 13533, 13551, 15333, 15511, 15531, 17313, 17391, 17737, 17913, 17997
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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133 is in the sequence because: (1) it is a lucky number, (2) the sum of its digits 1+3+3=7 is a lucky number, (3) the product of its digits 1*3*3=9 is a lucky number.
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MATHEMATICA
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lst = Range[1, 19172, 2]; i = 2; While[ i <= (len = Length@lst) && (k = lst[[i]]) <= len, lst = Drop[lst, {k, len, k}]; i++ ]; Select[lst, MemberQ[lst, Plus @@ IntegerDigits@# ] && MemberQ[lst, Times @@ IntegerDigits@# ] &] (* Robert G. Wilson v *)
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CROSSREFS
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Cf. A000959.
Sequence in context: A003033 A087147 A103115 this_sequence A127789 A112105 A065501
Adjacent sequences: A118556 A118557 A118558 this_sequence A118560 A118561 A118562
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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 07 2006
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EXTENSIONS
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Corrected and extended by Adam Panagos (adam.panagos(AT)gmail.com) and Robert G. Wilson v (rgwv(at)rgwv.com), May 10 2006
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