%I #14 Mar 22 2020 23:42:02
%S 45,4465,144453,544446,427444941,414446445,4440447441,444344944456,
%T 4404424444435,1046444944404441,14546344444444945,441441444448564440,
%U 4445444444946443841,444438244043444444046,4444844454444484014645,44641424644444444411441,4024414288444444444404441,44448461444441444448442420
%N Smallest triangular number containing exactly n 4's.
%t nsmall = Table[Infinity, 20];
%t For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
%t n0 = Count[IntegerDigits[p], 4];
%t If[nsmall[[n0]] > p, nsmall[[n0]] = p]];
%t ReplaceAll[nsmall, Infinity -> "?"] (* _Robert Price_, Mar 22 2020 *)
%Y Cf. A048359, A036517-A036526.
%K nonn,base
%O 1,1
%A _David W. Wilson_
%E a(12)-a(18) from _Giovanni Resta_, Oct 30 2019
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