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Search: id:A118783
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| A118783 |
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a(1) = 1. a(n) = (number of earlier terms of the sequence which are coprime to n)th positive integer not among the earlier terms of the sequence. |
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+0
2
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| 1, 2, 4, 3, 8, 5, 12, 9, 13, 11, 19, 15, 23, 21, 20, 25, 32, 18, 35, 24, 30, 29, 43, 28, 41, 37, 44, 38, 55, 27, 60, 47, 49, 51, 56, 42, 71, 54, 61, 50, 79, 46, 83, 63, 65, 68, 91, 59, 87, 67, 81, 75, 104, 66, 93, 77, 88, 85, 115, 57, 119, 96, 90, 99, 109, 73, 131, 102, 105, 80
(list; graph; listen)
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OFFSET
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1,2
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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The first 7 terms of the sequence are 1,2,4,3,8,5,12. Of these there are 3 terms that are coprime to 8 (those terms being 1, 3 and 5). So a(8) is the 3rd positive integer missing from the first 7 terms of the sequence (i.e. is the 3rd integer of the sequence 6, 7, 9, 10, 11, 13,..). So a(8) = 9.
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PROGRAM
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Contribution from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jul 30 2009: (Start)
(MAGMA) find:=function(S, k) c:=0; j:=0; while j lt #S and c lt k do j+:=1; if S[j] eq 0 then c+:=1; end if; end while; if c eq k then return j; else return 0; end if; end function;
z:=150; m:=70; W:=[ 0: n in [1..z] ]; V:=[1]; W[1]:=1; for n in [2..m] do c:=#[ j: j in [1..#V] | Gcd(n, V[j]) eq 1 ]; a:=find(W, c); if a eq 0 then break; end if; W[a]:=1; Append(~V, a); end for; print V; (End)
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CROSSREFS
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Cf. A118784.
Sequence in context: A131395 A109812 A137622 this_sequence A120242 A054427 A048672
Adjacent sequences: A118780 A118781 A118782 this_sequence A118784 A118785 A118786
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Apr 29 2006
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EXTENSIONS
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Extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jul 30 2009
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