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A352191 Records in A352187. 2
1, 2, 4, 6, 9, 12, 15, 18, 21, 24, 25, 30, 33, 36, 39, 42, 51, 56, 57, 77, 121, 207, 333, 345, 371, 391, 469, 871, 1111, 1121, 1341, 1557, 1719, 2043, 2051, 2367, 3421, 3951, 4527, 6127, 6849, 10307, 11007, 11061, 11079, 11133, 11511, 14113, 16753, 16839, 16911, 17973, 18153, 19161, 27731, 28831, 29447, 36949, 46783, 49093, 49577 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..61.

PROG

(Python)

from math import gcd

from itertools import count, islice

from sympy import primefactors

def A352191_gen(): # generator of terms

bset, blist, mmax, c = {1, 2}, [1, 2], 3, 2

yield from blist

while True:

for m in count(mmax):

if gcd(m, blist[-1]) > 1 and m not in bset:

if all(blist[-2] % p == 0 for p in primefactors(blist[-1])) or gcd(m, blist[-2]) == 1:

if m > c:

yield m

c = m

blist = [blist[-1], m]

bset.add(m)

while mmax in bset:

mmax += 1

break

A352191_list = list(islice(A352191_gen(), 30)) # Chai Wah Wu, Mar 14 2022

CROSSREFS

Cf. A352187, A352192.

Sequence in context: A030763 A143145 A328212 * A256393 A130664 A014011

Adjacent sequences: A352188 A352189 A352190 * A352192 A352193 A352194

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Mar 13 2022

STATUS

approved

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Last modified November 29 13:01 EST 2022. Contains 358429 sequences. (Running on oeis4.)