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A072557
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Let w(n) be defined by the following recurrence: w(1)=w(2)=w(3)=1, w(n)=(w(n-1)*w(n-2)+(w(n-1)+w(n-2))/3) / w(n-3); sequence gives values of n such that w(n) is an integer.
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3
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5, 11, 16, 17, 18, 23, 29, 34, 35, 36, 41, 47, 52, 53, 54, 59, 65, 70, 71, 72, 77, 83, 88, 89, 90, 95, 101, 106, 107, 108, 113, 119, 124, 125, 126, 131, 137, 142, 143, 144, 149, 155, 160, 161, 162, 167, 173, 178, 179, 180, 185, 191, 196, 197, 198, 203, 209, 214
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Denominators of w(k) are = 1,3 or 9 only.
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FORMULA
| lim n -> infinity a(n)/n = 18/5. sequence contains numbers of form (5+18k), (11+18k), (16+18k), (17+18k), (18+18k) k>=0.
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EXAMPLE
| First 11 values of w(n) are 5/3, 23/9, 17/3, 31/3, 25, 143/3, 353/3, 2039/9, 1685/3, 3251/3, 2689 which are integers fo k= 5 and 11 hence a(1)=5 a(2)=11
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CROSSREFS
| Cf. A072560, A072561.
Sequence in context: A137010 A137007 A137012 * A183989 A172327 A190323
Adjacent sequences: A072554 A072555 A072556 * A072558 A072559 A072560
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KEYWORD
| nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 06 2002
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