A069172 Smallest triangular number such that arithmetic mean of its digits = n (sum of the digits = n times the number of digits).

1, 105, 3, 435, 28, 6, 5995, 589598998999878

Offset: 1

Author

Robert G. Wilson v, Apr 09 2002

Keywords

• base
• fini
• full
• nonn

Comments

Because A045914 is complete, this sequence is complete. - Robert G. Wilson v, Oct 30 2013

Crossrefs

Cf. A069790.

Programs

Mathematica

Do[k = 1; While[ Apply[ Plus, IntegerDigits[k(k + 1)/2]] != n*Floor[ Log[10, k(k + 1)/2] + 1], k++ ]; Print[k(k + 1)/2], {n, 1, 7}]

Extensions

a(8) from Donovan Johnson, Mar 30 2010