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A048364
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a(n) is the index of the smallest triangular number containing exactly n 9's.
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1
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13, 44, 631, 1413, 28282, 76419, 282842, 1414213, 4471955, 31616419, 446313656, 1414001413, 6276925986, 44710913656, 44721356419, 632129732586, 527257052109, 14141923468538
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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nsmall = Table[Infinity, 20];
For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
n0 = Count[IntegerDigits[p], 9];
If[nsmall[[n0]] > i, nsmall[[n0]] = i]];
ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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