A036525 Smallest triangular number containing exactly n 8's.

28, 3828, 48828, 828828, 55888878, 3288888856, 78888885078, 388884828828, 13889888887878, 28888888883865, 8980885988888880, 88838888988888990, 983888888888812878, 8838888986888887878, 894885888888885888855, 78888888822845888188878, 1888886085781088888888878, 18788848888888828885888126

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• base

Crossrefs

Cf. A048363, A036517-A036526.

Programs

Mathematica

nsmall = Table[Infinity, 20];
For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
  n0 = Count[IntegerDigits[p], 8];
  If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)

Extensions

a(13)-a(18) from Giovanni Resta, Oct 30 2019