Search: id:A104172 Results 1-1 of 1 results found. %I A104172 %S A104172 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, %T A104172 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, %U A104172 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 %N A104172 Replace nonprimes in A005185 by zeros. %F A104172 a(n) = if Hofstadter[n] is prime then Hofstadter[n] else zero %t A104172 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}] %Y A104172 Cf. A005185. %Y A104172 Sequence in context: A021815 A075255 A135498 this_sequence A091408 A106242 A121474 %Y A104172 Adjacent sequences: A104169 A104170 A104171 this_sequence A104173 A104174 A104175 %K A104172 nonn %O A104172 0,3 %A A104172 Roger Bagula (rlbagulatftn(AT)yahoo.com), Mar 10 2005 Search completed in 0.001 seconds