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Search: id:A082270
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| A082270 |
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a(1) = 1; for n >= 1, a(n+1) = smallest number not occurring earlier such that a(n)*a(n+1) + 1 is a palindrome. |
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+0
4
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| 1, 2, 3, 7, 14, 10, 11, 21, 23, 32, 5, 13, 17, 29, 9, 6, 20, 8, 4, 19, 18, 28, 27, 22, 16, 34, 98, 135, 51, 146, 110, 101, 100, 102, 73, 220, 56, 131, 67, 43, 15, 12, 26, 38, 35, 181, 202, 50, 31, 215, 54, 111, 1891, 386, 45, 153, 130, 80, 125, 84, 398, 251, 70, 150, 68
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(51)=54; 54*1 + 1 = palindrome 55 but 1 occurs already at a(1); next 54*11 + 1 = 595 but 11 occurs already at a(7); next 54*14 + 1 = 757 but 14 occurs at a(5); next 54*17 + 1 = 919 but 17 occurs at a(13); ...; finally 54*111 + 1 = 5995 and 111 did not yet occur so 111 is included as next term a(52).
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CROSSREFS
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Cf. A081941, A082271.
Sequence in context: A128157 A073827 A081940 this_sequence A055688 A081941 A027957
Adjacent sequences: A082267 A082268 A082269 this_sequence A082271 A082272 A082273
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 02 2003, Apr 14 2003
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EXTENSIONS
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More terms from Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 09 2003.
Edited by N. J. A. Sloane (njas(AT)research.att.com) at the suggestion of Andrew Plewe, Jun 09 2007
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