A359075 Numbers that do not have two divisors with an equal sum of digits.

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 14, 15, 16, 17, 19, 23, 25, 26, 28, 29, 31, 32, 33, 34, 35, 37, 38, 39, 41, 43, 46, 47, 49, 51, 53, 55, 56, 57, 58, 59, 61, 62, 64, 65, 67, 68, 69, 71, 73, 74, 75, 76, 77, 78, 79, 82, 83, 85, 86, 87, 89, 91, 92, 93, 94, 95, 97

Offset

1,2

Links

Table of n, a(n) for n=1..68.

Mathematica

a={}; For[k=1, k<=97, k++, If[Length[Intersection[Table[Total[Part[IntegerDigits[Divisors[k]], i]], {i, DivisorSigma[0, k]}]]] == DivisorSigma[0, k], AppendTo[a, k]]]; a

Prog

(Python)
from sympy import divisors
def sod(n): return sum(map(int, str(n)))
def ok(n):
    s = set()
    for d in divisors(n, generator=True):
        sd = sod(d)
        if sd in s: return False
        s.add(sd)
    return True
print([k for k in range(1, 98) if ok(k)]) # Michael S. Branicky, Dec 15 2022
(PARI) isok(k) = my(d=divisors(k)); #Set(apply(sumdigits, d)) == #d; \\ Michel Marcus, Dec 19 2022

Crossrefs

Complement of A359074.

Cf. A000005, A007953, A359077 (proper divisors).

Sequence in context: A267215 A039219 A038365 * A247761 A031185 A342441

Adjacent sequences: A359072 A359073 A359074 * A359076 A359077 A359078

Keyword

nonn,base

Author

Stefano Spezia, Dec 15 2022

Status

approved