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 A163113 Fibonacci numbers containing equal numbers of prime digits and nonprime digits. 0
 13, 21, 34, 1597, 2584, 6765, 121393, 514229, 14930352, 24157817, 7778742049, 365435296162, 44945570212853, 184551825793033096366333, 781774079430987230203437, 7896325826131730509282738943634332893686268675876375 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS It is obvious that these numbers must contain an even number of digits. This sequence is probably finite. The equivalent sequences in bases 4, 6, and 8 are probably infinite. - Franklin T. Adams-Watters, Aug 06 2009 LINKS Table of n, a(n) for n=1..16. Simon Plouffe, Project Gutenberg EXAMPLE 24157817 is a Fibonacci number containing equal numbers of prime digits (2,5,7,7) and nonprime digits (4,1,8,1). MATHEMATICA pnpQ[n_]:=Module[{idn=IntegerDigits[n], len}, len=Length[idn]; EvenQ[len] && Count[idn, _?PrimeQ]==len/2]; Select[Fibonacci[Range[250]], pnpQ] (* Harvey P. Dale, May 01 2012 *) PROG (PARI) (digits(n, b=10)=local(r); r=[]; while(n>0, r=concat([n%b], r); n\=b); r); for(n=1, 500, v=digits(fibonacci(n)); np=sum(i=1, #v, isprime(v[i])); if(#v==2*np, print1(fibonacci(n)", "))) CROSSREFS Cf. A000045. Sequence in context: A164451 A164432 A034292 * A164496 A164459 A164453 Adjacent sequences: A163110 A163111 A163112 * A163114 A163115 A163116 KEYWORD nonn,base AUTHOR Parthasarathy Nambi, Jul 21 2009 EXTENSIONS Edited and extended by Franklin T. Adams-Watters, Aug 06 2009 STATUS approved

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Last modified November 29 20:23 EST 2023. Contains 367447 sequences. (Running on oeis4.)