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Search: id:A117737
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| A117737 |
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Numbers such that the (positive) difference between the sum of the digits and the product of the digits is a primenumber. |
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+0
1
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| 20, 24, 25, 27, 29, 30, 33, 34, 35, 37, 38, 42, 43, 45, 47, 49, 50, 52, 53, 54, 56, 57, 59, 65, 67, 70, 72, 73, 74, 75, 76, 78, 79, 83, 87, 92, 94, 95, 97, 101, 102, 104, 106, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 125, 126, 128, 131, 133, 140
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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97 is in the sequence because (1)the sum of its digits is 16,(2)the product of its digits is 63 and the difference between 16 and 63 is 47, which is a prime.
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PROGRAM
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(PARI) sudig(i, suOrmul)= { local(nshft, resul) ; nshft = i ; resul = nshft % 10 ; nshft = nshft \ 10 ; while(nshft>0, if(suOrmul==0, resul += nshft % 10, resul *= nshft % 10 ) ; nshft \= 10 ; ) ; return(resul) ; } { for(n=10, 150, summ = sudig(n, 0) ; mull = sudig(n, 1) ; if( isprime(summ-mull), print1(n, ", ") ) ; ) ; } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 21 2006
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CROSSREFS
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Cf. A000040.
Adjacent sequences: A117734 A117735 A117736 this_sequence A117738 A117739 A117740
Sequence in context: A013339 A031169 A093716 this_sequence A062908 A111323 A114843
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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), Apr 14 2006
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 21 2006
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