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A134463 Values of n such that 5n^2 + 5n + 1 is a palindromic prime. +0
2
1, 4, 5, 565, 475081 (list; graph; listen)
OFFSET

1,2

COMMENT

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.

LINKS

Eric Weisstein, Link to a section of The World of Mathematics. Palindromic Prime.

Wikipedia: Centered decagonal number.

MATHEMATICA

Do[ f=5k^2+5k+1; If[ PrimeQ[f] && FromDigits[ Reverse[ IntegerDigits[ f ] ] ] == f, Print[ k ] ], {k, 1, 500000} ]

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.

Adjacent sequences: A134460 A134461 A134462 this_sequence A134464 A134465 A134466

Sequence in context: A051152 A042181 A042717 this_sequence A058916 A064612 A005927

KEYWORD

more,nonn,base

AUTHOR

Alexander Adamchuk (alex(AT)kolmogorov.com), Oct 26 2007

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Last modified October 13 20:18 EDT 2008. Contains 145016 sequences.


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