A104172 Replace nonprimes in A005185 with zeros.

0, 0, 2, 3, 3, 0, 5, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 17, 17, 0, 0, 19, 0, 0, 0, 0, 23, 23, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 31, 0, 0, 0, 0, 0, 37, 0, 0, 0, 0, 0, 0, 0, 41, 43, 0, 43, 43, 0, 0, 0, 47, 47, 0, 0, 0, 0, 0, 0, 0, 0, 41

Offset

0,3

Links

Table of n, a(n) for n=0..96.

Formula

a(n) = if Hofstadter[n] is prime then Hofstadter[n] else zero

Mathematica

digits = 200 Hofstadter[n_Integer? Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n - 1]] + Hofstadter[n - Hofstadter[n - 2]] Hofstadter[0] = Hofstadter[1] = 1 b = Table[If[PrimeQ[ Hofstadter[n]] == True, Hofstadter[n], 0], {n, 0, digits - 1}]

Crossrefs

Cf. A005185.

Sequence in context: A359788 A075255 A135498 * A091408 A193382 A106242

Adjacent sequences: A104169 A104170 A104171 * A104173 A104174 A104175

Keyword

nonn

Author

Roger L. Bagula, Mar 10 2005

Status

approved