A395542 Numbers whose number of nonzero digits is identical in base 2 and 5.

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

Offset

1,3

Comments

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

Links

Vincenzo Manto, Table of n, a(n) for n = 1..10000

Maple

q:= n-> (f-> f(n, 2)=f(n, 5))((k, b)-> nops(subs(0=[][], convert(k, base, b)))):
select(q, [$0..230])[];

Mathematica

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

Prog

(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)])
(PARI) isok(k) = #select(x->x>0, digits(k, 2)) == #select(x->x>0, digits(k, 5)); \\ Michel Marcus, Apr 28 2026

Crossrefs

Cf. A393803, A000120, A276134.

Sequence in context: A022778 A156022 A224809 * A048171 A090178 A327094

Adjacent sequences: A395537 A395538 A395539 * A395543 A395544 A395545

Keyword

nonn,base

Author

Vincenzo Manto, Apr 28 2026

Status

approved