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A117697 Palindromic primes in base 2 (written in base 2). 9
11, 101, 111, 10001, 11111, 1001001, 1101011, 1111111, 100000001, 100111001, 110111011, 10010101001, 10110101101, 11000100011, 11001010011, 11011111011, 11100100111, 11101010111, 1001100011001, 1001111111001, 1010001000101 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Attila Olah, Table of n, a(n) for n=1..43964

Eric Weisstein: Palindromic Prime.

FORMULA

a(n) = A007088(A016041(n)). - R. J. Mathar, Feb 25 2007

MAPLE

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;

            end if;

        end do ;

        return true;

    else

        false ;

    end if ;

end proc:

for i from 1 to 900 do p := ithprime(i) : if isA016041(p) then printf("%d, ", A007088(p)) ; fi ; od : # R. J. Mathar, Feb 25 2007

MATHEMATICA

pal2Q[n_] := Reverse[x = IntegerDigits[n, 2]] == x; BaseForm[Select[Prime[Range[700]], pal2Q[#] &], 2] (* Jayanta Basu, Jun 24 2013 *)

CROSSREFS

Cf. A016041, A002385.

Sequence in context: A076289 A247647 A240602 * A091366 A158051 A073064

Adjacent sequences:  A117694 A117695 A117696 * A117698 A117699 A117700

KEYWORD

nonn,base

AUTHOR

Martin Renner, Apr 13 2006

EXTENSIONS

Keyword:base added by R. J. Mathar, Jul 12 2009

STATUS

approved

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Last modified May 3 12:13 EDT 2016. Contains 272360 sequences.