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Search: id:A117697
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| A117697 |
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Palindromic primes in base 2 (written in base 2). |
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+0
4
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| 11, 101, 111, 10001, 11111, 1001001, 1101011, 1111111, 100000001, 100111001, 110111011, 10010101001, 10110101101, 11000100011, 11001010011, 11011111011, 11100100111, 11101010111, 1001100011001, 1001111111001, 1010001000101
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Attila Olah, Table of n, a(n) for n=1..43964
Eric Weisstein: Palindromic Prime.
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FORMULA
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a(n)=A007088[A016041(n)]. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 25 2007
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MAPLE
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A007088 := proc(n) local bin, dig ; bin := convert(n, base, 2) ; add( op(dig, bin)*10^(dig-1), dig=1..nops(bin) ) ; end: isA016041 := proc(n) local bin, dig ; if isprime(n) then bin := convert(n, base, 2) ; for dig from 1 to nops(bin)/2 do if op(dig, bin) <> op(-dig, bin) then RETURN(false) ; fi ; od ; RETURN(true) ; else false ; fi ; end: for i from 1 to 900 do p := ithprime(i) : if isA016041(p) then printf("%d, ", A007088(p)) ; fi ; od : - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 25 2007
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CROSSREFS
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Cf. A016041, A002385.
Sequence in context: A099821 A057148 A076289 this_sequence A091366 A158051 A073064
Adjacent sequences: A117694 A117695 A117696 this_sequence A117698 A117699 A117700
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KEYWORD
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nonn,base
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AUTHOR
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Martin Renner (martin.renner(AT)gmx.net), Apr 13 2006
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EXTENSIONS
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Keyword:base added by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 12 2009
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