A086074 Number of 3's in decimal expansion of triangular number n(n+1)/2.

0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 2, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 0

Offset

0,78

Links

Table of n, a(n) for n=0..104.

Mathematica

DigitCount[#, 10, 3]&/@Accumulate[Range[0, 110]] (* _Harvey P. Dale_, Aug 01 2017 *)

Crossrefs

Cf. 0's A086071, 1's A086072, 2's A086073, 4's A086075, 5's A086076, 6's A086077, 7's A086078, 8's A086079, 9's A086080.

Sequence in context: A374076 A353970 A037827 * A180601 A331048 A381212

Adjacent sequences: A086071 A086072 A086073 * A086075 A086076 A086077

Keyword

base,nonn

Author

_Jason Earls_, Jul 08 2003

Status

approved