OFFSET
0,2
COMMENTS
Also permutable multiples of 4: numbers k such that every permutation of the digits of k is a multiple of 4.
FORMULA
a(n) = 4*A007089(n).
EXAMPLE
480 = 4*120, 408 = 4*102, 840 = 4*210, 804 = 4*201, 048 = 4*12, 084 = 4*21.
MAPLE
f:= proc(n) local L, i;
L:= convert(n, base, 3);
4*add(L[i]*10^(i-1), i=1..nops(L))
end proc:
map(f, [$0..100]); # Robert Israel, Apr 30 2021
MATHEMATICA
FromDigits /@ Tuples[{0, 4, 8}, 4] (* Amiram Eldar, Apr 30 2021 *)
PROG
(PARI) a(n) = fromdigits(digits(n, 3))*4 \\ Rémy Sigrist, May 05 2021
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Ctibor O. Zizka, Apr 30 2021
STATUS
approved