A140491 Trajectory of 2 under repeated application of the map: n -> n + third-smallest number that does not divide n.

2, 7, 11, 15, 21, 26, 31, 35, 39, 44, 50, 56, 62, 67, 71, 75, 81, 86, 91, 95, 99, 104, 110, 116, 122, 127, 131, 135, 141, 146, 151, 155, 159, 164, 170, 176, 182, 187, 191, 195, 201, 206, 211, 215, 219, 224, 230, 236, 242, 247, 251, 255, 261, 266, 271, 275, 279, 284, 290, 296

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

NestList[Complement[Range[3+#], Divisors[#]][[3]]+#&, 2, 60] (* Harvey P. Dale, Jan 15 2024 *)

Prog

(PARI) third(n) = {my(nb = 0, k = 1); while (nb != 3, if (n % k, nb++); if (nb != 3, k++); ); k; }
f(n) = n + third(n);
lista2(nn) = {a = 2; print1(a, ", "); for (n=2, nn, newa = f(a); print1(newa, ", "); a = f(a); ); } \\ Michel Marcus, Oct 04 2018

Crossrefs

Cf. A140485, A140486, A140487, A140488, A140489 (second-smallest sequences).

Cf. A140490, A140492, A140493, A140494 (third-smallest sequences).

Sequence in context: A184485 A001960 A174008 * A122823 A063289 A287726

Adjacent sequences: A140488 A140489 A140490 * A140492 A140493 A140494

Keyword

nonn

Author

Jacques Tramu, Jun 25 2008

Extensions

More terms from Michel Marcus, Oct 04 2018

Status

approved