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Search: id:A118809
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| A118809 |
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a(1) = 1. a(n) = (number of earlier terms which divide n)th positive integer not occurring among the earlier terms of the sequence. |
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+0
2
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| 1, 2, 3, 5, 6, 9, 4, 10, 11, 13, 8, 16, 12, 14, 17, 20, 15, 22, 7, 25, 21, 24, 18, 31, 26, 28, 27, 33, 19, 36, 29, 35, 34, 37, 38, 44, 30, 40, 39, 47, 23, 48, 32, 49, 46, 45, 42, 57, 50, 54, 51, 55, 41, 61, 56, 63, 58, 59, 52, 70, 53, 62, 67, 68, 64, 72, 60, 73, 66, 77, 43, 83
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Likely a permutation of the positive integers.
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EXAMPLE
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The first 7 terms of the sequence are 1,2,3,5,6,9,4. Of these there are 3 terms (1, 2 and 4) that divide 8, so we want for a(8) the 3rd positive integer not among the first 7 terms of the sequence (i.e. we want the third term of 7,8,10,11,...). So a(8)= 10.
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MAPLE
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A118809 := proc(nmin) local a, anxt, i, n, j ; a := [1] ; while nops(a) < nmin do n := nops(a)+1 ; i := 0 ; for j in a do if n mod j = 0 then i := i+1 ; fi ; od: anxt := 0 ; while i > 0 do anxt := anxt+1 ; while anxt in a do anxt := anxt+1 ; od ; i := i-1; od ; a := [op(a), anxt] ; od; a ; end: A118809(100) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 06 2007
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CROSSREFS
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Cf. A118810.
Sequence in context: A128994 A098211 A073673 this_sequence A121048 A075389 A053784
Adjacent sequences: A118806 A118807 A118808 this_sequence A118810 A118811 A118812
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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), Apr 30 2006
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 06 2007
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