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Search: id:A118064
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| A118064 |
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Decimal expansion of the sum of the reciprocals of the palindromic primes (Honaker's constant). |
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1
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OFFSET
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1,2
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COMMENT
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The sum using all palindromic numbers <10^11 is 1.32398... Extrapolating using palindromic primes <10^8 using Wynn's epsilon method gives a value near 1.3240... - Eric Weisstein (eric(AT)weisstein.com), May 14 2006
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LINKS
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Carlos Rivera: Problems & Puzzles: Puzzle 056 - The Honaker's Constant.
Eric Weisstein: Palindromic Prime.
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FORMULA
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a(n) = sum(1/p), p is a palindromic prime.
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MATHEMATICA
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(* first obtain nextPalindrome from A007632 *) s = 1/11; c = 1; pp = 1; Do[ While[pp < 10^n, If[PrimeQ@ pp, c++; s = N[s + 1/pp, 64]]; pp = NextPalindrome@ pp]; If[ OddQ@ n, pp = 10^(n + 1); Print[{s, n, c}]], {n, 17}] [From Robert G. Wilson v (rgwv(AT)rgwv.com), May 31 2009]
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CROSSREFS
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Cf. A002385, A160910.
Cf. A050251. [From Robert G. Wilson v (rgwv(AT)rgwv.com), May 31 2009]
Sequence in context: A089750 A109591 A143932 this_sequence A070471 A070690 A160387
Adjacent sequences: A118061 A118062 A118063 this_sequence A118065 A118066 A118067
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KEYWORD
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cons,nonn,more
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AUTHOR
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Martin Renner (martin.renner(AT)gmx.net), May 11 2006
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EXTENSIONS
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Corrected by Eric Weisstein (eric(AT)weisstein.com), May 14 2006
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