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Search: id:A114996
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| A114996 |
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a(n) = smallest palindrome > a(n-1) (for n > 0) such that the sum of its prime digits is equal to palindrome with index n, or -1 if none exists. |
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+0
1
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| 0, -1, 2, 3, 22, 151, 222, 232, 323, 333, 353, 37273, 77577, 7772777, 377777773, 5777777775, 77777777777, 27777777777772, 577777757777775, 577777777777775, 37777777777777773, 2777777775777777772, 7777777775777777777
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Palindrome with index n is A002113(n).
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EXAMPLE
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a(0) = 0 since A002113(0) = 0 and the prime digits of 0 sum to 0.
a(1) = -1 since A002113(1) = 1 and there is no number (all the more no palindrome) whose prime digits sum to 1.
a(5) = 151 since A002113(5) = 5, and 151 is the smallest palindrome > a(4) = 22 whose prime digits sum to 5.
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CROSSREFS
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Cf. A002113.
Sequence in context: A032810 A062921 A083178 this_sequence A137077 A046965 A119679
Adjacent sequences: A114993 A114994 A114995 this_sequence A114997 A114998 A114999
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KEYWORD
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base,sign
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AUTHOR
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Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), Feb 23 2006
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EXTENSIONS
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Edited, corrected and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Mar 13 2006
a(16) and a(19) corrected, a(21) and a(22) added by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), May 23 2007
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