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A120947
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a(n) = smallest m such that n-th prime divides Pell(m).
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0
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2, 4, 3, 6, 12, 7, 8, 20, 22, 5, 30, 19, 10, 44, 46, 27, 20, 31, 68, 70, 36, 26, 84, 44, 48, 51, 34, 108, 55, 28, 126, 132, 17, 140, 75, 150, 79, 164, 166, 87, 36, 91, 190, 96, 9, 18, 212, 74, 76, 23, 116, 14, 40, 84, 64, 262, 15, 270, 139, 140, 284, 49, 308, 310, 78, 159, 332
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| For all divisors d of n>0, Pell(d) divides Pell(n), so if a prime divides the n-th Pell number, so does it for all multiples of n.
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EXAMPLE
| a(4)=6 because the 6th Pell number, 70, is the first that is divisible by the 4th prime (=7).
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CROSSREFS
| Cf. A000129 (Pell numbers), A001602 (equivalent sequence with Fibonacci numbers).
Sequence in context: A002326 A064273 A134561 * A046793 A182940 A101278
Adjacent sequences: A120944 A120945 A120946 * A120948 A120949 A120950
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KEYWORD
| nonn
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AUTHOR
| Ralf Stephan (ralf(AT)ark.in-berlin.de), Aug 19 2006
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