OFFSET

1,2

COMMENTS

The sequence is conjectured to be a permutation of the positive integers.

LINKS

Scott R. Shannon, Image of the first 75000 terms. The green line is y = n.

EXAMPLE

a(15) = 27 as a(14) = 10, and 27 has not yet appeared, is coprime to 10, is not 1 more than 10, and has no digit in common with 10. Note that 21 satisfies all of these conditions except the last. This is the first term to differ from A353904.

PROG

(Python)

from math import gcd

from itertools import islice

def c(san, k): return set(san) & set(str(k)) == set()

def agen(): # generator of terms

an, aset, mink = 1, {1}, 2

while True:

yield an

k, san = mink, str(an)

while k in aset or gcd(an, k) != 1 or k-an == 1 or not c(san, k):

k += 1

an = k

aset.add(an)

while mink in aset: mink += 1

print(list(islice(agen(), 75))) # Michael S. Branicky, May 23 2022

CROSSREFS

KEYWORD

nonn,base

AUTHOR

Scott R. Shannon, May 07 2022

STATUS

approved