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A347757
Indices of local minima in A347113.
3
1, 8, 11, 20, 28, 37, 51, 53, 101, 116, 136, 146, 159, 213, 302, 318, 440, 520, 638, 698, 702, 912, 1031, 1128, 1528, 1758, 1832, 1891, 2107, 2198, 2523, 2671, 2857, 3069, 3760, 3892, 3946, 4256, 4438, 4638, 4880, 5022, 5656, 6092, 6147, 6322, 6470, 6492, 6579
OFFSET
1,2
COMMENTS
a(n)-1 = last instance of A347756(n) in A347755.
a(n+1) > a(n) + 1, since terms in A347113 are distinct by definition.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..6904 (terms 1..898 from Michael De Vlieger)
MATHEMATICA
Block[{nn = 2^13, a = {1}, c, k, m, u = 2, v}, v = a; Map[Set[c[#], 1] &, Union@ a]; Do[Set[k, u]; If[PrimeQ[#], m = 2; While[IntegerQ[c[m #]], m++]; k = m #, While[Or[IntegerQ[c[k]], k == #, GCD[k, #] == 1], k++]] &[a[[-1]] + 1]; AppendTo[a, k]; Set[c[k], 1]; AppendTo[v, u]; If[k == u, While[IntegerQ[c[u]], u++]], nn]; Map[FirstPosition[a, #][[1]] &, Most@ Union@ v]]
(* or using A347113 bfile: *)
Block[{a, u = {1}, v = 1}, a = Import["https://oeis.org/A347113/b347113.txt", "Data"][[All, -1]]; Do[If[a[[i]] == v, While[! FreeQ[a[[1 ;; i]], v], v++]]; AppendTo[u, v], {i, Length[a]}]; Map[FirstPosition[a, #][[1]] &, Most@ Union@ u] ]
PROG
(Python)
from math import gcd
A347757_list, nset, m, j, i = [1], {1}, 2, 2, 1
for _ in range(10**4):
i += 1
k = m
while k == j or gcd(k, j) == 1 or k in nset:
k += 1
j = k + 1
nset.add(k)
if k == m:
A347757_list.append(i)
while m in nset:
m += 1 # Chai Wah Wu, Sep 13 2021
CROSSREFS
Cf. A347113, A347306 (indices of records in A347113), A347755, A347756.
Sequence in context: A213084 A243520 A129730 * A368356 A291664 A318347
KEYWORD
nonn
AUTHOR
Michael De Vlieger, Sep 12 2021
STATUS
approved