A086075 Number of 4's in decimal expansion of triangular number n(n+1)/2.

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

Offset: 0

Author

Jason Earls, Jul 08 2003

Keywords

• base
• nonn

Links

• Paolo Xausa, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. 0's A086071, 1's A086072, 2's A086073, 3's A086074, 5's A086076, 6's A086077, 7's A086078, 8's A086079, 9's A086080.

Programs

Mathematica

DigitCount[Accumulate[Range[0, 100]], 10, 4] (* Paolo Xausa, May 05 2024 *)