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Search: id:A118577
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| A118577 |
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a(1) = 1. For m >= 0 and 1 <= k <= 2^m, a(2^m +k) = number of earlier terms of the sequence which are coprime to a(k). |
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1
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| 1, 1, 2, 3, 4, 5, 4, 6, 8, 9, 5, 8, 6, 11, 7, 6, 16, 17, 9, 13, 11, 19, 13, 11, 15, 18, 23, 17, 14, 26, 28, 14, 32, 33, 19, 26, 20, 33, 21, 15, 23, 29, 37, 26, 18, 40, 41, 19, 28, 47, 37, 46, 47, 50, 49, 50, 37, 25, 55, 57, 33, 35, 34, 34, 64, 65, 39, 51, 41, 57, 43, 31, 45, 54, 61
(list; graph; listen)
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OFFSET
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1,3
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EXAMPLE
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8 = 2^2 + 4; so for a(8) we want the number of terms among terms a(1), a(2),... a(7) which are coprime to a(4) = 3. So a(8) = 6.
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PROGRAM
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(PARI) A118577(mmax)= { local(a, ncopr); a=[1]; for(m=0, mmax, for(k=1, 2^m, ncopr=0; for(i=1, 2^m+k-1, if( gcd(a[k], a[i])==1, ncopr++; ); ); a=concat(a, ncopr); ); ); return(a); } { print(A118577(6)); } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 30 2006
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CROSSREFS
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Adjacent sequences: A118574 A118575 A118576 this_sequence A118578 A118579 A118580
Sequence in context: A017860 A017850 A137912 this_sequence A135681 A135680 A135682
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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), May 24 2006
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), May 30 2006
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