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Search: id:A117385
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| A117385 |
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Positive integers, each occurring twice in the sequence, such that a(n) = a(k) when n+k = 5*a(n), starting with a(1)=1 and filling the next vacant position with the smallest unused number. |
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3
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| 1, 2, 3, 1, 4, 5, 6, 2, 7, 8, 9, 3, 10, 11, 4, 12, 13, 14, 5, 15, 16, 17, 6, 18, 19, 7, 20, 21, 22, 8, 23, 24, 25, 9, 26, 27, 10, 28, 29, 30, 11, 31, 32, 12, 33, 34, 35, 13, 36, 37, 38, 14, 39, 40, 15, 41, 42, 43, 16, 44, 45, 46, 17, 47, 48, 18, 49, 50, 51, 19, 52, 53, 20, 54, 55, 56
(list; graph; listen)
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OFFSET
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1,2
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FORMULA
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a(5*a(n)-n) = a(n). Conjecture: Lim_inf a(n)/n = (5-sqrt(5))/10; Lim_sup a(n)/n = (5+sqrt(5))/10.
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PROGRAM
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(PARI) {a(n)=local(A=vector(n), m=1); for(k=1, n, if(A[k]==0, A[k]=m; if(5*m-k<=#A, A[5*m-k]=m); m+=1)); A[n]}
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CROSSREFS
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Cf. A117384 (a(4*a(n)-n)=a(n)), A117386 (a(6*a(n)-n)=a(n)).
Sequence in context: A055442 A055439 A122005 this_sequence A071517 A046671 A129566
Adjacent sequences: A117382 A117383 A117384 this_sequence A117386 A117387 A117388
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Mar 11 2006
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