Vincenzo Manto

A395542

Created: 4/29/2026 | Author: Vincenzo Manto , Apr 28 2026

Numbers whose number of nonzero digits is identical in base 2 and 5.

Numbers k such that A000120(k) = A276134(k).

Sequence Chart

Graph of A395542

Data

0,1,2,4,6,9,12,17,18,24,37,38,40,41,42,44,49,56,65,67,69,73,74,80,81,82,84,88,97,98,112,129,130,131,133,134,137,138,146,148,152,156,163,166,169,172,176,184,197,198,209,212,216,232,259,260,261,262,266,268

Computational Implementations

PYTHON

def nonzero_digits(n, b):
    count = 0
    while n > 0:
        if n % b: count += 1
        n //= b
    return count
def ok(n):
    return nonzero_digits(n, 2) == nonzero_digits(n, 5)
print([k for k in range(270) if ok(k)])

CODE

isok(k) = #select(x->x>0, digits(k,2)) == #select(x->x>0, digits(k,5)); \\ _Michel Marcus_, Apr 28 2026

Mathematica

q[k_] := DigitCount[k, 2, 1] == Total[DigitCount[k, 5, {1, 2, 3, 4}]]; Select[Range[0, 230], q]

Cross-References

See also OEIS entries: Cf. A393803, A000120, A276134.