OFFSET
1,1
EXAMPLE
Squarefree part of 624=2^4*3*13 is 39. Digit_sum(624)=12, digit_sum(39)=12
PROG
(PARI)
digsum(n)={local (d, p); d=0; p=n; while(p, d+=p%10; p=floor(p/10)); return(d)}
{for (n=4, 10^3, m=core(n); if(digsum(n)==digsum(m)&&m<>n, print(n))); }
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
Antonio Roldán, Oct 16 2013
STATUS
approved