A372899 Numbers k that divide the k-th companion Pell number.

1, 2, 6, 18, 54, 66, 162, 198, 486, 594, 726, 1314, 1458, 1782, 2178, 2838, 3222, 3942, 4374, 5346, 5778, 5874, 6534, 7986, 8514, 8646, 9666, 11826, 13122, 14454, 16038, 17334, 17622, 19602, 23958, 25542, 25938, 28998, 31218, 35442, 35478, 39366, 43362, 48114

Offset

1,2

Comments

Numbers k such that k | A002203(k).

Links

Amiram Eldar, Table of n, a(n) for n = 1..327

Example

2 is a term since A002203(2) = 6 = 2 * 3 is divisible by 2.
6 is a term since A002203(6) = 198 = 6 * 33 is divisible by 6.

Mathematica

Select[Range[50000], Divisible[LucasL[#, 2], #] &]

Prog

(PARI) lista(kmax) = {my(p1 = 2, p2 = 6, p3); print1("1, 2, "); for(k = 3, kmax, p3 = p1 + 2*p2; if(!(p3 % k), print1(k, ", ")); p1 = p2; p2 = p3); }

Crossrefs

Cf. A002203.

Similar sequences: A014847 (Catalan), A016089 (Lucas), A023172 (Fibonacci), A051177 (partition), A232570 (tribonacci), A246692 (Pell), A266969 (Motzkin).

Sequence in context: A120010 A132790 A358417 * A214799 A072850 A254941

Adjacent sequences: A372896 A372897 A372898 * A372900 A372901 A372902

Keyword

nonn

Author

Amiram Eldar, May 16 2024

Status

approved