A239111 Smallest Pell number (see A000129) divisible by n-th prime.

2, 12, 5, 70, 13860, 169, 408, 15994428, 93222358, 29, 107578520350, 6625109, 2378, 24580185800219268, 143263821649299118, 7645370045, 15994428, 259717522849, 37774750930342781945186508, 220167382952941249990598278, 21300003689580, 3166815962, 50305164660422142002238655969020

Offset: 1

Author

N. J. A. Sloane, Mar 27 2014

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..350
• J. L. Schiffman, Exploring the Fibonacci sequence of order two with CAS technology, Paper C027, Electronic Proceedings of the Twenty-fourth Annual International Conference on Technology in Collegiate Mathematics, Orlando, Florida, March 22-25, 2012.

Crossrefs

Cf. A120947.

Programs

Maple

p:= proc(n) p(n):=`if`(n<2, n, 2*p(n-1)+p(n-2)) end:
a:= proc(n) local k, t; t:= ithprime(n);
      for k while irem(p(k), t)>0 do od; p(k)
    end:
seq(a(n), n=1..23);  # Alois P. Heinz, Mar 28 2014

Mathematica

p[n_] := p[n] = If[n<2, n, 2*p[n-1] + p[n-2]]; a[n_] := With[{t = Prime[n]} , For[k=1, Mod[p[k], t] > 0, k++]; p[k]]; Table[a[n], {n, 1, 23}] (* Jean-François Alcover, Feb 14 2016, after Alois P. Heinz *)