A362133 Smallest indices k where A362131(k) = A362132(n).

1, 3, 5, 7, 9, 12, 17, 31, 36, 41, 58, 74, 82, 112, 160, 189, 198, 220, 294, 325, 914, 1267, 1389, 1872, 1927, 1957, 2032, 2155, 2184, 2302, 2358, 2835, 3047, 3672, 3794, 3832, 3873, 3924, 4543, 4785, 35502, 98365, 1728198, 8375015

Offset: 1

Author

Michael De Vlieger, Apr 10 2023

Keywords

• nonn
• more

Comments

Next term exceeds 2^28, if it exists.

Links

• Michael De Vlieger, Plot (log_2 a(n), A362132(n)) at (x, y).

Crossrefs

Cf. A360179, A362131, A362132.

Programs

Mathematica

nn = 2^20;
c[] := False; q[] := False; h[] := 0; f[n] := DivisorSigma[0, n];
a[1] = j = u = w = 1;
{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], q[k], j}, {k, True, k}];
      While[h[u] == 0, u++];
      If[k == w, While[q[w], w++]; Sow[n]], {n, 2, nn}] ][[-1, -1]]