The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A359075 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A359075

Numbers that do not have two divisors with an equal sum of digits.
(history; published version)

#9 by N. J. A. Sloane at Wed Dec 21 20:22:14 EST 2022

STATUS

proposed

approved

#8 by Michel Marcus at Mon Dec 19 04:49:07 EST 2022

STATUS

editing

proposed

#7 by Michel Marcus at Mon Dec 19 04:49:00 EST 2022

PROG

(PARI) isok(k) = my(d=divisors(k)); #Set(apply(sumdigits, d)) == #d; \\ Michel Marcus, Dec 19 2022

STATUS

proposed

editing

#6 by Stefano Spezia at Thu Dec 15 14:28:16 EST 2022

STATUS

editing

proposed

#5 by Stefano Spezia at Thu Dec 15 13:16:26 EST 2022

CROSSREFS

Cf. A000005, A007953.

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

#4 by Michael S. Branicky at Thu Dec 15 13:02:56 EST 2022

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

#3 by Stefano Spezia at Thu Dec 15 10:46:33 EST 2022

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

CROSSREFS

Cf. A000005, A007953.Complement of A359074.

Complement of A359074.

#2 by Stefano Spezia at Thu Dec 15 10:45:51 EST 2022

NAME

allocated for Stefano SpeziaNumbers that do not have two divisors with an equal sum of digits.

DATA

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

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

CROSSREFS

Cf. A000005, A007953.Complement of A359074.

KEYWORD

allocated

nonn,base

AUTHOR

Stefano Spezia, Dec 15 2022

STATUS

approved

editing

#1 by Stefano Spezia at Thu Dec 15 10:39:37 EST 2022

NAME

allocated for Stefano Spezia

KEYWORD

allocated

STATUS

approved