A116069 Numbers k such that k has nonincreasing digits and the k-th prime has nondecreasing digits.

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

Cf. A116066, A116067, A116068.

Sequence in context: A160015 A276392 A132271 * A081511 A030283 A276633

Adjacent sequences: A116066 A116067 A116068 * A116070 A116071 A116072

Keyword

nonn,base

Author

Giovanni Resta, Feb 13 2006

Status

approved