A086076 - OEIS

%I #7 Dec 15 2017 17:36:32

%S 0,0,0,0,0,1,0,0,0,1,2,0,0,0,1,0,0,1,0,0,0,0,1,0,0,1,1,0,0,1,1,0,1,1,

%T 2,0,0,0,0,0,0,0,0,0,0,1,0,0,0,1,1,0,0,0,1,1,1,1,0,0,0,0,1,0,0,1,0,0,

%U 0,1,1,2,0,0,1,1,0,0,0,0,0,0,0,0,1,2,0,0,0,1,1,0,0,0,1,1,1,1,1,1,2,2,2,2,1

%N Number of 5's in decimal expansion of triangular number n(n+1)/2.

%t DigitCount[#,10,5]&/@Accumulate[Range[0,110]] (* _Harvey P. Dale_, Sep 24 2016 *)

%Y Cf. 0's A086071, 1's A086072, 2's A086073, 3's A086074, 4's A086075, 6's A086077, 7's A086078, 8's A086079, 9's A086080.

%K base,nonn

%O 0,11

%A _Jason Earls_, Jul 08 2003