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A262661
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Minimal nested palindromic base-8 primes with seed 1; see Comments.
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3
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1, 111, 1411141, 12141114121, 10412141114121401, 11610412141114121401611, 171161041214111412140161171, 303171161041214111412140161171303, 3230317116104121411141214016117130323, 71323031711610412141114121401611713032317
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OFFSET
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1,2
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COMMENTS
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Using only base-8 digits 0,1,2,3,4,5,6,7 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-8 primes with seed s.
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LINKS
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EXAMPLE
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a(3) = 1411141 is the least base-8 prime having a(2) = 111 in its middle. Triangular format:
1
111
1411141
12141114121
10412141114121401
11610412141114121401611
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MATHEMATICA
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s = {1}; base = 8; 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 (* A262661 *)
Map[FromDigits[ToString[#], base] &, s] (* A262662 *)
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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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