A355063 Perfect powers whose digits are in nonincreasing order and do not include 0.

1, 4, 8, 9, 32, 64, 81, 441, 841, 961, 7744, 7776, 8874441, 9853321, 999887641

Offset

1,2

Comments

a(16) > 10^45 if it exists. - Michael S. Branicky, Jun 19 2022

Links

Table of n, a(n) for n=1..15.

Prog

(Python)
from sympy import perfect_power as pp
from itertools import count, islice, combinations_with_replacement as mc
def agen():
    yield 1
    for d in count(1):
        nd = (int("".join(m)) for m in mc("987654321", d))
        yield from sorted(filter(pp, nd))
print(list(islice(agen(), 14))) # Michael S. Branicky, Jun 16 2022
(PARI) isok(m) = if (ispower(m), my(d=digits(m)); vecmin(d) && (d == vecsort(d, , 4))); \\ Michel Marcus, Jun 17 2022

Crossrefs

Cf. A001597, A009996, A028822, A062826.

Sequence in context: A115656 A076705 A306916 * A162752 A076966 A360758

Adjacent sequences: A355060 A355061 A355062 * A355064 A355065 A355066

Keyword

nonn,base,more

Author

Jon E. Schoenfield, Jun 16 2022

Status

approved