OFFSET
1,2
LINKS
K. D. Bajpai, Table of n, a(n) for n = 1..12445
EXAMPLE
a(3) = 3240 = 80 * (80 + 1)/2 is a triangular number. Since 3240 is divisible by (3 + 2 + 4 + 0)^2 = 81, it appears in the sequence.
a(3) = 3321 = 81 * (81 + 1)/2 is a triangular number. Since 3321 is divisible by (3 + 3 + 2 + 1)^2 = 81, it appears in the sequence.
MATHEMATICA
Select[Table[n*(n + 1)/2, {n, 10000}], Divisible[#, Plus @@ IntegerDigits[#]^2] &]
PROG
(PARI)
for(n=1, 10^4, s=n*(n+1)/2; if(s%(sumdigits(s)^2)==0, print1(s, ", "))) \\ Derek Orr, Aug 23 2014
CROSSREFS
KEYWORD
nonn,base
AUTHOR
K. D. Bajpai, Aug 20 2014
STATUS
approved