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A118717
Sum of two consecutive semiprimes.
8
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
OFFSET
1,1
FORMULA
a(n) = A001358(n) + A001358(n+1).
MATHEMATICA
Total /@ Partition[Select[Range[50000], 2 == PrimeOmega[#] &], 2, 1] (* Zak Seidov, Jan 31 2017 *)
PROG
(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, May 23 2006
CROSSREFS
Cf. A001358.
Sequence in context: A343550 A285176 A135363 * A181529 A232501 A138593
KEYWORD
nonn
AUTHOR
Luc Stevens (lms022(AT)yahoo.com), May 21 2006
EXTENSIONS
Corrected and extended by R. J. Mathar, May 23 2006
Edited by Ray Chandler, Oct 31 2010
STATUS
approved