A064568 n-th term in Recamán's sequence A005132 is divisible by n.

1, 3, 11, 21, 39, 76, 248, 844, 1520, 2752, 9317, 17223, 31221, 57071, 99741, 589932, 58056875, 101769229, 302890748, 511561220, 904036924, 39488697700, 325374626148

Offset

1,2

Comments

No more terms < 4.61*10^11. - Jud McCranie, Dec 29 2019.

Links

Table of n, a(n) for n=1..23.

Index entries for sequences related to Recamán's sequence

Example

A005132(21) = 63, 63 is divisible by 21, so 21 is in the sequence.

Mathematica

With[{s = Nest[Append[#1, If[And[#3 > 0, FreeQ[#1, #3]], #3, #1[[-1]] + #2]] & @@ {#1, #2, #1[[-1]] - #2} & @@ {#, Length@ #} &, {0}, 10^5]}, Reap[Do[If[Mod[s[[i]], i] == 0, Sow[i]], {i, Length@ s - 1}]][[-1, -1]]] (* Michael De Vlieger, Dec 29 2019 *)

Crossrefs

Cf. A005132, A064569.

Sequence in context: A082485 A322595 A317298 * A147073 A147191 A327607

Adjacent sequences: A064565 A064566 A064567 * A064569 A064570 A064571

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 16 2001

Extensions

Offset changed, a(1), a(22)-a(23) from Jud McCranie, Dec 29 2019

Status

approved