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A134463
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Values of n such that 5n^2 + 5n + 1 is a palindromic prime.
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1
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OFFSET
| 1,2
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COMMENTS
| Corresponding Centered decagonal palindromic primes are 5a(n)^2 + 5a(n) + 1 = A134462 = {11,101,151,1598951,1128512158211, ...}. Note that the first 4 terms of a(n) are the palindromes.
a(9) > 1414213562372. - Donovan Johnson, Feb 13 2011
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LINKS
| Eric Weisstein, Link to a section of The World of Mathematics. Palindromic Prime.
Wikipedia: Centered decagonal number.
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MATHEMATICA
| Do[ f=5k^2+5k+1; If[ PrimeQ[f] && FromDigits[ Reverse[ IntegerDigits[ f ] ] ] == f, Print[ k ] ], {k, 1, 500000} ]
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CROSSREFS
| Cf. A134462 = Centered decagonal palindromic primes; or palindromic primes of the form 5n^2 + 5n + 1. 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.
Sequence in context: A051152 A042181 A042717 * A058916 A064612 A005927
Adjacent sequences: A134460 A134461 A134462 * A134464 A134465 A134466
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KEYWORD
| more,nonn,base
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AUTHOR
| Alexander Adamchuk (alex(AT)kolmogorov.com), Oct 26 2007
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EXTENSIONS
| a(6), a(7) from D. S. McNeil (d.mcneil(AT)qmul.ac.uk), Mar 02 2009
a(8) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 13 2011
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