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A116069
Numbers k such that k has nonincreasing digits and the k-th prime has nondecreasing digits.
4
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 22, 30, 31, 33, 41, 50, 51, 52, 55, 70, 72, 73, 75, 77, 87, 88, 91, 92, 95, 200, 222, 332, 333, 430, 633, 644, 654, 733, 861, 862, 872, 887, 986, 6666, 7655, 7662, 86540, 86543, 86550, 86552, 86553, 86621, 86622, 86630, 86631
OFFSET
1,2
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..75 (all terms < 10^9)
EXAMPLE
p(86543) = 1111189.
PROG
(Python)
from sympy import sieve
from itertools import count, islice, combinations_with_replacement as mc
def nd(n): s = str(n); return s == "".join(sorted(s))
def bgen(d):
ni = map(int, ("".join(m) for m in mc("9876543210", d)))
yield from sorted(k for k in ni if k != 0)
def agen():
for d in count(1):
yield from (k for k in bgen(d) if nd(sieve[k]))
print(list(islice(agen(), 55))) # Michael S. Branicky, Jun 26 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, Feb 13 2006
STATUS
approved