A069516 Geometric mean of digits = 3 and digits are in nondecreasing order.

3, 19, 33, 139, 333, 1199, 1339, 3333, 11399, 13339, 33333, 111999, 113399, 133339, 333333, 1113999, 1133399, 1333339, 3333333, 11119999, 11133999, 11333399, 13333339, 33333333, 111139999, 111333999, 113333399, 133333339, 333333333, 1111199999, 1111339999

Offset

1,1

Comments

No number is obtainable by permuting the digits of other members - only one with ascending order of digits is included.

Links

Michael S. Branicky, Table of n, a(n) for n = 1..10000

Example

1339 belongs to this sequence but 1933 does not.

Mathematica

a = {}; b = 3; Do[c = Apply[ Times, IntegerDigits[n]]/b^Floor[ Log[10, n] + 1]; If[c == 1 && Position[a, FromDigits[ Sort[ IntegerDigits[n]]]] == {}, Print[n]; a = Append[a, n]], {n, 1, 10^8}]

Prog

(Python)
from math import prod
from sympy.utilities.iterables import multiset_combinations
def aupton(terms):
  n, digits, alst, powsexps3 = 0, 1, [], [(1, 0), (3, 1), (9, 2)]
  while n < terms:
    target = 3**digits
    mcstr = "".join(str(d)*(digits//max(1, r)) for d, r in powsexps3)
    for mc in multiset_combinations(mcstr, digits):
      if prod(map(int, mc)) == target:
        n += 1
        alst.append(int("".join(mc)))
        if n == terms: break
    else: digits += 1
  return alst
print(aupton(31)) # Michael S. Branicky, Apr 28 2021

Crossrefs

Cf. A061427, A069512, A069518.

Sequence in context: A056246 A360081 A061427 * A098856 A178201 A062291

Adjacent sequences: A069513 A069514 A069515 * A069517 A069518 A069519

Keyword

nonn,base

Author

Amarnath Murthy, Mar 30 2002

Extensions

Edited and extended by Robert G. Wilson v, Apr 01 2002

Name edited and a(30) and beyond from Michael S. Branicky, Apr 28 2021

Status

approved