A387074 Indices of record high points in A386482.

1, 2, 3, 4, 6, 7, 10, 12, 18, 19, 25, 27, 30, 32, 45, 53, 58, 75, 77, 116, 124, 127, 143, 145, 190, 196, 197, 208, 237, 288, 311, 321, 369, 454, 480, 685, 833, 838, 1035, 1089, 1207, 1290, 1426, 1498, 1533, 2080, 2668, 2785, 2888, 3031, 3782, 4003, 4965, 5748

Offset

1,2

Links

Chai Wah Wu, Table of n, a(n) for n = 1..178 (terms 1..140 from Michael De Vlieger)

Mathematica

Block[{c, j, k, m, p, r, nn},
  nn = 6000; c[_] := False; m[_] := 1; j = 2; c[1] = c[2] = True; r = 0;
  {1, 2}~Join~Monitor[Reap[Do[
    If[PrimePowerQ[j],
      Set[{p, k, m}, {#1, #1^(#2 - 1), #1^(#2 - 1)}] & @@
        FactorInteger[j][[1]]; While[And[c[k*p], k != 0], k--];
        If[k == 0, k = m; While[c[k*p], k++]]; k *= p,
      k = j - 1; While[And[Or[c[k], CoprimeQ[j, k]], k != 1], k--];
        If[k == 1, k += j; While[Or[c[k], CoprimeQ[j, k] ], k++] ] ];
    If[k > r, r = k; Sow[n]];
    Set[{c[k], j}, {True, k}], {n, 3, nn}] ][[-1, 1]], n] ]

Prog

(Python)
from math import gcd
from itertools import count, islice
def A387074_gen(): # generator of terms
    m, mset, c, a = 2, {2}, 3, 2
    yield from (1, 2)
    for j in count(3):
        for i in range(m-1, c-1, -1):
            if i not in mset and gcd(i, m)>1:
                if i>a:
                    yield j
                    a = i
                break
        else:
            for i in count(max(c, m+1)):
                if i not in mset and gcd(i, m)>1:
                    if i>a:
                        yield j
                        a = i
                    break
        m = i
        mset.add(i)
        while c in mset:
            mset.remove(c)
            c += 1
A387074_list = list(islice(A387074_gen(), 30)) # Chai Wah Wu, Sep 10 2025

Crossrefs

Cf. A386482, A387073.

Sequence in context: A328172 A239468 A336815 * A355979 A119793 A181436

Adjacent sequences: A387071 A387072 A387073 * A387075 A387076 A387077

Keyword

nonn

Author

Michael De Vlieger, Aug 15 2025

Status

approved