A362128 Indices of records in A360179.

1, 3, 5, 7, 9, 12, 15, 21, 25, 29, 52, 69, 87, 100, 138, 176, 233, 252, 265, 338, 371, 384, 400, 447, 459, 492, 515, 594, 606, 677, 779, 794, 850, 896, 1100, 1144, 1204, 1225, 1243, 1584, 1674, 1700, 2214, 2239, 2265, 2338, 2568, 3014, 3621, 3652, 4027, 4058, 4437, 4464, 4584, 4625, 5111, 5201, 5281

Offset

1,2

Links

Michael De Vlieger, Table of n, a(n) for n = 1..8238

Mathematica

nn = 6000; c[_] := False; h[_] := 0; f[n_] := DivisorSigma[0, n];
a[1] = j = u = 1; r = 0;
{1}~Join~Rest@ Reap[Do[
      If[c[j],
        k = j + f[u]; h[j]++; h[u]--,
        k = f[j]; c[j] = True; h[j]++ ];
      u = Min[u, j]; Set[{a[n], j}, {k, k}]; While[h[u] == 0, u++];
      If[k > r, r = k; Sow[n]], {n, 2, nn}] ][[-1, -1]]

Crossrefs

Cf. A000005, A360179, A362127.

Sequence in context: A226331 A333601 A316312 * A118015 A265057 A122643

Adjacent sequences: A362125 A362126 A362127 * A362129 A362130 A362131

Keyword

nonn

Author

Michael De Vlieger, Apr 09 2023

Status

approved