A361512 Indices of novel terms in A361511.

1, 3, 5, 7, 9, 12, 14, 18, 21, 25, 28, 32, 39, 42, 47, 53, 59, 67, 71, 77, 80, 88, 94, 100, 106, 115, 120, 128, 134, 142, 147, 154, 161, 170, 178, 187, 196, 205, 217, 226, 236, 246, 256, 266, 280, 287, 302, 313, 327, 334, 348, 359, 374, 383, 394, 406, 416, 431

Offset

1,2

Links

Michael De Vlieger, Table of n, a(n) for n = 1..17905 (all terms m <= 2^24)

Mathematica

nn = 432; c[_] = False; f[n_] := DivisorSigma[0, n]; a[1] = m = 1; Reap[Do[(If[c[#], a[n] = # + f[a[m]] ; m++, a[n] = f[#] ; Sow[n - 1]]; c[#] = True) &[a[n - 1]], {n, 2, nn}] ][[-1, -1]] (* Michael De Vlieger, Apr 08 2023 *)

Crossrefs

Cf. A361511.

Sequence in context: A139130 A219087 A186705 * A361516 A361515 A072154

Adjacent sequences: A361509 A361510 A361511 * A361513 A361514 A361515

Keyword

nonn

Author

N. J. A. Sloane, Apr 08 2023

Status

approved