login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A104172 Replace nonprimes in A005185 with zeros. 0
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 (list; graph; refs; listen; history; text; internal format)
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: A238525 A075255 A135498 * A091408 A193382 A106242

Adjacent sequences:  A104169 A104170 A104171 * A104173 A104174 A104175

KEYWORD

nonn

AUTHOR

Roger L. Bagula, Mar 10 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified April 25 10:11 EDT 2017. Contains 285379 sequences.