A060396 Values of k associated with A060395.

1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 1, 0, 0, 0, 0, 0, 1

Offset: 0

Author

N. J. A. Sloane, Apr 04 2001

Keywords

• nonn
• easy

Comments

a(2n) = 0 for n >= 1. a(3n) = 0 for n >= 1. a(6n+1) = 1 for n >= 0. - Nathaniel Johnston, Apr 30 2011

Links

• Carlos Rivera, Conjecture 17. The Ludovicus conjecture about the Euler trinomials, The Prime Puzzles & Problems Connection.

Programs

Mathematica

a[n_] := Switch[n, 0, 1, 1, 1, , Module[{f, kmax0 = 2}, f[kmax] := f[kmax] = MinimalBy[Table[{k, FactorInteger[k^2 + k + n][[1, 1]]}, {k, 0, kmax}], Last, 1]; f[kmax = kmax0]; f[kmax = 2 kmax]; While[f[kmax] != f[kmax/2], kmax = 2 kmax]; f[kmax][[1, 1]]]];
Table[a[n], {n, 0, 101}] (* Jean-François Alcover, Aug 15 2022 *)

Extensions

Name corrected and a(15)-a(97) from Nathaniel Johnston, Apr 30 2011