OFFSET
1,3
LINKS
J. Mulder, Table of n, a(n) for n = 1..20000
FORMULA
a(n) | A007955(n). - R. J. Mathar, May 26 2016
MAPLE
A140211 := proc(n)
a := 1;
for d in numtheory[divisors](n) do
if modp(d, 4) = 3 then
a := a*d ;
end if;
end do:
a;
end proc: # R. J. Mathar, Dec 15 2015
MATHEMATICA
ListProduct[lst_] := Fold[Times, 1, lst] lst = {}; For[n = 1, n <= 1000, n++, AppendTo[lst, ListProduct[Select[Divisors[n], Mod[ #, 4] == 3 &]]]] lst (* Jasper Mulder (jasper.mulder(AT)planet.nl), Jul 15 2009 *)
PROG
(PARI) a(n) = my(p=1); fordiv(n, d, if ((d % 4)==3, p*=d)); p; \\ Michel Marcus, Jan 07 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
R. J. Mathar, Jun 27 2008
STATUS
approved