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A345663
Numbers k such that A001414(k) is divisible by A007953(k).
1
1, 2, 3, 4, 5, 7, 10, 27, 32, 42, 60, 70, 91, 100, 110, 114, 115, 124, 130, 132, 143, 154, 170, 182, 185, 188, 200, 204, 215, 220, 221, 222, 230, 232, 238, 242, 266, 276, 295, 308, 315, 326, 338, 342, 378, 402, 437, 450, 472, 485, 494, 532, 540, 555, 572, 576, 583, 588, 612, 620, 624, 636, 648
OFFSET
1,2
LINKS
EXAMPLE
a(10) = 42 is a term because A001414(42) = 2+3+7 = 12 is divisible by A007953(42) = 4+2 = 6.
MAPLE
filter:= proc(n) local t;
add(t[1]*t[2], t=ifactors(n)[2]) mod convert(convert(n, base, 10), `+`) = 0
end proc:
select(filter, [$1..1000]);
MATHEMATICA
Select[Range[650], Divisible[Plus @@ Times @@@ FactorInteger[#], Plus @@ IntegerDigits[#]] &] (* Amiram Eldar, Jun 21 2021 *)
PROG
(PARI) sopfr(n) = my(f=factor(n)); sum(k=1, #f~, f[k, 1]*f[k, 2]);
isok(k) = !(sopfr(k) % sumdigits(k)); \\ Michel Marcus, Jun 24 2021
CROSSREFS
KEYWORD
nonn,base
AUTHOR
J. M. Bergot and Robert Israel, Jun 21 2021
STATUS
approved