OFFSET
1,1
COMMENTS
Is this A004611 without the 1? - R. J. Mathar, Jul 16 2020
a(n) = A004611(n+1) for (at least) n <= 10^6. - Hugo Pfoertner, Oct 17 2020
EXAMPLE
MAPLE
isA129904 := proc(k)
local i, j ;
if modp(k, 6) = 1 and k> 1 then
for i from 0 to k-1 do
j := k-1-i ;
return true;
end if;
end do:
false ;
else
false;
end if;
end proc:
for k from 1 to 400 do
if isA129904(k) then
printf("%d, ", k) ;
end if;
end do:
PROG
(PARI) isA129904(k)={my(a003215(n)=3*n*(n+1)+1); if(k%6!=1||k<=1, 0, for(i=0, k-1, my(j=k-1-i); if(a003215(i)%k==0&&a003215(j)%k==0, return(1)))); 0};
for(k=1, 500, if(isA129904(k), print1(k, ", "))) \\ Hugo Pfoertner, Oct 17 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Mats Granvik, Jun 04 2007
EXTENSIONS
Extended by R. J. Mathar, Dec 16 2016
STATUS
approved