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A262655
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Minimal nested palindromic base-6 primes with seed 5; see Comments.
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3
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5, 151, 11511, 5115115, 13511511531, 5135115115315, 15513511511531551, 1155135115115315511, 14115513511511531551141, 131411551351151153155114131, 51314115513511511531551141315, 11551314115513511511531551141315511, 11511551314115513511511531551141315511511
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OFFSET
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1,1
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COMMENTS
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Using only base-6 digits 0,1,2,3,4,5, let s be a palindrome and put a(1) = s. Let a(2) be the least palindromic prime having s in the middle; for n > 2, let a(n) be the least palindromic prime have a(n-1) in the middle. Then (a(n)) is the sequence of minimal nested palindromic base-6 primes with seed s.
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LINKS
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EXAMPLE
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a(3) = 11511 is the least base-6 prime having a(2) = 151 in its middle.
Triangular format:
5
151
11511
5115115
13511511531
5135115115315
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MATHEMATICA
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s = {5}; base = 6; z = 20; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#, base]], base]] &];
AppendTo[s, FromDigits[IntegerDigits[tmp, base]]], {z}]; s (* A262655 *)
Map[FromDigits[ToString[#], base] &, s] (* A262656 *)
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CROSSREFS
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KEYWORD
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nonn,easy,base
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AUTHOR
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STATUS
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approved
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