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A123386
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Largest difference between successive semiprimes up to 10^n inclusive.
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1
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3, 7, 14, 24, 38, 47, 74, 74, 95, 112, 146
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| There are 4 semiprimes up to 10^1 {4, 6, 9, 10}. The differences between successive semiprimes are {2, 3, 1}. Thus a(1) = Max[ {2, 3, 1} ] = 3.
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PROG
| (PARI) A001358(prev)={ local(a=prev+1) ; while(bigomega(a)!=2, a++ ; ) ; return(a) ; } A123386(n)={ local(sp1=4, sp2=6, a=2) ; while(sp2<=10^n, a=max(a, sp2-sp1) ; sp1=sp2 ; sp2=A001358(sp1) ; ) ; return(a) ; } { for(n=1, 13, print(A123386(n)) ; ) ; } - 2 more term from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 17 2008
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CROSSREFS
| Cf. A001358, A065516, A036352, A038460, A053303.
Sequence in context: A140462 A093523 A173247 * A060999 A089187 A179178
Adjacent sequences: A123383 A123384 A123385 * A123387 A123388 A123389
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KEYWORD
| hard,more,nonn
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Nov 09 2006
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EXTENSIONS
| 2 more term from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 17 2008
a(8)-a(9) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Sep 05 2008
a(10)-a(11) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Apr 14 2010
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