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Search: id:A082584
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| A082584 |
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Fractal palindromic primes of first order. |
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+0
4
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| 313, 353, 373, 383, 727, 757, 787, 797, 11311, 11411, 1311131, 1317131, 1513151, 1917191, 9196919, 9199919, 10301110301, 10301910301, 10501210501, 10501910501, 10601110601, 12421212421, 12421812421, 12721612721
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A first order fractal palindromic prime is one of the form WmW, where either wing W about a central digit m, is itself a palindromic prime, which, however, may not be further split in this manner to maintain the property.
[Log_10(A082584)] must be of the form k2. - Robert G. Wilson v (rgwv(at)rgwv.com), Jul 22 2005
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EXAMPLE
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12421812421 is in the sequence because it is a concatenation of the palindromic prime part 12421 with itself, hinging over the central 8;12421 cannot however be split into simpler palindromic primes in this way.
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MATHEMATICA
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f[n_] := Block[{m = n}, pd = IntegerDigits[m]; pd = Take[pd, Floor[Length[pd]/2]]; If[PrimeQ[m] && PrimeQ[FromDigits[pd]] && pd == Reverse[pd] && m == FromDigits[Reverse[IntegerDigits[m]]] && ! f[FromDigits[pd]], True, False]]; Do[ If[ f[n], Print[n]], {n, 10^10}] - Robert G. Wilson v (rgwv(at)rgwv.com), Jul 22 2005
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CROSSREFS
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Cf. A002385.
Sequence in context: A097023 A139656 A061323 this_sequence A088282 A068687 A093808
Adjacent sequences: A082581 A082582 A082583 this_sequence A082585 A082586 A082587
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KEYWORD
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base,nonn
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AUTHOR
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Lekraj Beedassy (blekraj(AT)yahoo.com), May 07 2003
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