A048361
a(n) is the index of the smallest triangular number containing exactly n 6's.
Original entry on oeis.org
3, 11, 36, 363, 3366, 8563, 35963, 394123, 3055048, 11531588, 115464831, 115470036, 1154484036, 10645763163, 35401884036, 152754484036, 365148371588, 2292012515963, 33065591380305, 115470003521836, 642442319075676, 1154701378423588, 10996978373724908, 36347397889274188, 230810167309875091
Offset: 1
Cf.
A036523,
A048351,
A048355,
A048356,
A048357,
A048358,
A048359,
A048360,
A048362,
A048363,
A048364,
A048541.
-
nsmall = Table[Infinity, 20];
For[i = 0, i <= 10^6, i++, p = PolygonalNumber[i];
n0 = Count[IntegerDigits[p], 6];
If[nsmall[[n0]] > i, nsmall[[n0]] = i]];
ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)
A036513
Smallest square containing exactly n 6's.
Original entry on oeis.org
16, 676, 46656, 1666681, 26666896, 4666665969, 26661664656, 616686666436, 12666666068676, 696626660666596, 16666569616666761, 64666665664666569, 666566667666656964, 16656666666663616576, 6466267667066666666596, 46366666666326666766276
Offset: 1
-
a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 6] != n, k++]; k^2]; Array[a, 6] (* Giovanni Resta, Jul 27 2018 *)
A048350
a(n)^2 is the smallest square containing exactly n 5's.
Original entry on oeis.org
5, 75, 235, 745, 22485, 22925, 235065, 505525, 2356384, 23569166, 227069495, 674919666, 3931354166, 7450205075, 39969432765, 524933839166, 2134374738666, 4904646324166, 23802428354166, 159861050770834, 725227930760773, 1882963768916666, 7586668936732745, 74536940878685015, 174801474694453186
Offset: 1
-
k := 1; For[n = 1, n < 30000, n++, If[DigitCount[n^2][[5]] == k, k++; Print[n]]] (* Stefan Steinerberger, Apr 09 2006 *)
a[n_] := Module[{i = 1}, While[DigitCount[i^2][[6]] != n, i++;]; i]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 20 2006 *)
Showing 1-3 of 3 results.
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