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A362133 Smallest indices k where A362131(k) = A362132(n). 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Next term exceeds 2^28, if it exists.
LINKS
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]]
CROSSREFS
Sequence in context: A265059 A349828 A096231 * A373706 A100432 A261033
KEYWORD
nonn,more
AUTHOR
Michael De Vlieger, Apr 10 2023
STATUS
approved

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Last modified June 23 07:33 EDT 2024. Contains 373629 sequences. (Running on oeis4.)