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Search: id:A115207
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| A115207 |
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a(1)=1. a(n) = number of earlier terms of the sequence which when added to n produce a composite number. |
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+0
4
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| 1, 0, 1, 1, 3, 2, 5, 5, 7, 4, 8, 5, 10, 9, 11, 10, 14, 10, 13, 16, 14, 16, 18, 18, 19, 20, 16, 20, 21, 23, 23, 25, 23, 27, 30, 23, 27, 27, 31, 27, 33, 31, 31, 33, 37, 31, 41, 31, 41, 39, 40, 34, 43, 45, 47, 36, 45, 40, 50, 43, 51, 44, 47, 50, 56, 41, 56, 53, 55, 47, 61, 55, 60, 57
(list; graph; listen)
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OFFSET
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1,5
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EXAMPLE
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Adding 7 to the first 6 terms of the sequence gives [8,7,8,8,10,9]. Of these termsfive are composite, so a(7) = 5.
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PROGRAM
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(PARI) seq=vector(200); seq[1]=1; print1(1, ", "); for(j=1, 190, count=0; for(k=1, j, if(isprime(j+1+seq[k])==0 && (j+1+seq[k])>1, count=count+1; )); seq[j+1]=count; print1(seq[j+1], ", ")) - Matthew Conroy Feb 09 2006
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CROSSREFS
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Cf. A115208, A115209, A115210.
Sequence in context: A141297 A059319 A019828 this_sequence A093048 A141732 A008623
Adjacent sequences: A115204 A115205 A115206 this_sequence A115208 A115209 A115210
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Jan 16 2006
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EXTENSIONS
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More terms from Matthew Conroy Feb 09 2006
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