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A177461 The smallest k such that Fibonacci(n)+k and Fibonacci(n)-k are both prime. 3
0, 0, 0, 3, 0, 2, 3, 12, 0, 5, 0, 24, 3, 4, 0, 33, 48, 28, 57, 192, 0, 31, 12, 60, 81, 28, 0, 177, 108, 50, 345, 150, 168, 35, 6, 618, 735, 76, 18, 147, 0, 134, 111, 126, 0, 85, 642, 1146, 225, 92, 480, 219, 348, 466, 345, 72, 300, 89, 90, 312, 2025, 664, 168, 945, 276, 128 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,4

COMMENTS

Indices where a(n)= 0 are provided by A001605.

LINKS

Table of n, a(n) for n=3..68.

FORMULA

a(n) = A047160(A000045(n)). - R. J. Mathar, Jan 23 2011

EXAMPLE

3 +- 0 -> primes, 5 +- 0 -> primes, 8 +- 3 -> primes, 13 +- 0 -> primes, 21 +- 2 -> primes, ...

MAPLE

A047160 := proc(n) for k from 0 to n-1 do if isprime(n-k) and isprime(n+k) then return k; end if; end do: return -1 ; end proc:

A177461 := proc(n) A047160(combinat[fibonacci](n)) ; end proc: # R. J. Mathar, Jan 23 2011

MATHEMATICA

f[n_] := Block[{k}, If[n==2||OddQ[n], k=0, k=1]; While[!PrimeQ[n-k] || !PrimeQ[n+k], k+=2]; k]; Table[f[Fibonacci[n]], {n, 3, 100}]

CROSSREFS

Cf. A000045.

Sequence in context: A001608 A159977 A245251 * A201924 A112974 A113069

Adjacent sequences:  A177458 A177459 A177460 * A177462 A177463 A177464

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, May 09 2010

STATUS

approved

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Last modified September 16 08:17 EDT 2021. Contains 347469 sequences. (Running on oeis4.)