A089124 Largest prime factor of numbers of the form A^2 + 3.

2, 7, 3, 19, 7, 13, 13, 67, 7, 103, 31, 7, 43, 199, 19, 37, 73, 109, 13, 31, 37, 487, 19, 193, 157, 97, 61, 787, 211, 43, 241, 79, 13, 61, 307, 433, 7, 1447, 127, 229, 421, 31, 463, 277, 13, 163, 79, 769, 601, 2503, 31, 2707, 37, 139, 757, 73, 271, 37, 67, 1201, 19

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[70]^2+3) (* Harvey P. Dale, Jun 17 2020 *)

Prog

(PARI) largeasqp3(m) = { for(a=1, m, y=a^2 + 3; f = factor(y); v = component(f, 1); v1 = v[length(v)]; print1(v1", ")

Crossrefs

Cf. A049423.

Sequence in context: A112303 A336854 A209666 * A210662 A229610 A117809

Adjacent sequences: A089121 A089122 A089123 * A089125 A089126 A089127

Keyword

easy,nonn

Author

Cino Hilliard, Dec 05 2003

Status

approved