OFFSET
1,3
PROG
(PARI) istri(n)=for(k=0, n+1, if(k*(k+1)/2==n, return(1))); 0
for(n=0, 10^3, N=n*(n+1)/2; d=digits(N); s=0; for(i=1, #d, s+=d[i]*(d[i]+1)/2); if(istri(s), print1(N, ", ")))
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Derek Orr, Feb 11 2015
STATUS
approved