The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A089123 Smallest prime factor of numbers of the form A^2 + 3. 1
 2, 7, 2, 19, 2, 3, 2, 67, 2, 103, 2, 3, 2, 199, 2, 7, 2, 3, 2, 13, 2, 487, 2, 3, 2, 7, 2, 787, 2, 3, 2, 13, 2, 19, 2, 3, 2, 1447, 2, 7, 2, 3, 2, 7, 2, 13, 2, 3, 2, 2503, 2, 2707, 2, 3, 2, 43, 2, 7, 2, 3, 2, 3847, 2, 4099, 2, 3, 2, 7, 2, 4903, 2, 3, 2, 5479, 2, 5779, 2, 3, 2, 19, 2, 7, 2, 3, 2, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 REFERENCES H. Rademacher, Lectures on Elementary Number Theory, pp. 33-38. LINKS Harvey P. Dale, Table of n, a(n) for n = 1..1000 MATHEMATICA FactorInteger[#][[1, 1]]&/@(Range[90]^2+3) (* Harvey P. Dale, Apr 22 2018 *) PROG (PARI) smallasqp3(m) = { for(a=1, m, y=a^2 + 3; f = factor(y); v = component(f, 1); v1 = v[length(v)]; print1(v[1]", ") ) } CROSSREFS Cf. A002496. Sequence in context: A222654 A318059 A212835 * A281751 A282366 A281897 Adjacent sequences: A089120 A089121 A089122 * A089124 A089125 A089126 KEYWORD easy,nonn AUTHOR Cino Hilliard, Dec 05 2003 STATUS approved

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

Last modified June 13 15:42 EDT 2024. Contains 373389 sequences. (Running on oeis4.)