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Search: id:A118717
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| A118717 |
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Sum of two consecutive semiprimes. |
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+0
1
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| 10, 15, 19, 24, 29, 36, 43, 47, 51, 59, 67, 69, 73, 77, 85, 95, 100, 106, 112, 115, 120, 127, 134, 143, 151, 159, 167, 171, 173, 178, 184, 187, 189, 201, 217, 226, 233, 237, 240, 243, 245, 252, 262, 267, 275, 283, 285, 288, 291, 301, 313, 317, 320, 327, 335
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n)=q(n)+q(n+1) with q(n) a semiprime
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PROGRAM
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(PARI) isA001358(n)= { local(f, fct, sumpo); if(n <4, return(0) ); f=factor(n); fct=(matsize(f))[1]; sumpo= sum(i=1, fct, f[i, 2]); if ( sumpo != 2, return(0), return(1) ); } { oldn=0; for(n=4, 200, if( isA001358(n)==1, if( oldn !=0, print1(oldn+n, ", "); ); oldn=n; ); ); } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 23 2006
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CROSSREFS
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Cf. A001358.
Sequence in context: A091049 A139540 A135363 this_sequence A138593 A004259 A006623
Adjacent sequences: A118714 A118715 A118716 this_sequence A118718 A118719 A118720
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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 21 2006
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EXTENSIONS
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Corrected and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 23 2006
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