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Search: id:A134462
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| A134462 |
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Centered decagonal palindromic primes; or palindromic primes of the form 5n^2 + 5n + 1. |
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+0
2
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| 11, 101, 151, 1598951, 1128512158211, 104216919612401, 107635959536701
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n) is an intersection of the Palindromic primes = A002385(n) = {2, 3, 5, 7, 11, 101, 131, 151, ...} and the Centered 10-gonal numbers = A062786(n) = {1, 11, 31, 61, 101, 151, ...}. Corresponding numbers n such that 5n^2 + 5n + 1 is a term of A134462 are listed in A134463 = {1, 4, 5, 565, 475081, ...}. Note that the first 4 terms of A134463 are the palindromes.
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LINKS
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Eric Weisstein, Link to a section of The World of Mathematics. Palindromic Prime.
Wikipedia: Centered decagonal number.
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MATHEMATICA
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Do[ f=5k^2+5k+1; If[ PrimeQ[f] && FromDigits[ Reverse[ IntegerDigits[ f ] ] ] == f, Print[ f ] ], {k, 1, 500000} ]
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CROSSREFS
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Cf. A002385 = Palindromic primes. Cf. A062786 = Centered 10-gonal numbers. Cf. A090562 = Primes of the form 5k^2 + 5k + 1. Cf. A090563 = Values of n such that 5n^2 + 5n + 1 is a prime. Cf. A134463 = Values of n such that 5n^2 + 5n + 1 is a palindromic prime.
Sequence in context: A052035 A083144 A058411 this_sequence A156753 A118592 A156617
Adjacent sequences: A134459 A134460 A134461 this_sequence A134463 A134464 A134465
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KEYWORD
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more,nonn,base
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Oct 26 2007
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EXTENSIONS
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More terms from Tomas J. Bulka (tbulka(AT)rodincoil.com), Aug 30 2009
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