A263225 Positive values of n such that A027961(n) is divisible by A000217(n).

1, 60, 240, 600, 660, 768, 1008, 1200, 1320, 1800, 1860, 2160, 2688, 2736, 3000, 3300, 3360, 3888, 4620, 4800, 5280, 5520, 5568, 6120, 6480, 6720, 6840, 7320, 7680, 8208, 8640, 9000, 9600, 9720, 10368, 11160, 12240, 12288, 13200, 13248, 13440, 13680, 13868, 14400, 15120, 15360

Offset: 1

Author

Altug Alkan, Oct 12 2015

Keywords

• nonn
• easy

Comments

Is there a maximum value of a(n) - a(n-1)?

A263161 is not a subsequence although they have many common terms.

Terms that are not congruent to 0 (mod 6): 1, 13868, 16016, 34988, 158252, 196412, 313988, 1287788, 2056748, 2212412, 2542028, 2847260, 2951708, 6117548, 7538108, 7756988, 9056732, 9865628, ... . - Robert G. Wilson v, Oct 15 2015

Examples

			For n = 1, A027961(1) = 1 is divisible by A000217(1) = 1.
For n = 60, A027961(60) = 9062201101800 = 1830*4952022460, therefore it is divisible by A000217(60) = 1830.
		

Crossrefs

Cf. A000204, A000217, A027961, A263161.

Programs

Magma

[n: n in [1..20000] | IsDivisibleBy(Lucas(n+2)-3,n*(n+1) div 2)]; // Bruno Berselli, Oct 19 2015

Mathematica

fQ[n_] := Mod[ Fibonacci[n + 1] + Fibonacci[n + 3] - 3, n (n + 1)/2] == 0; Select[ Range@ 16000, fQ] (* Robert G. Wilson v, Oct 15 2015 *)

PARI

for(n=1, 20000, if((fibonacci(n+3) + fibonacci(n+1)-3) % (n*(n+1)/2) == 0, print1(n", ")));