A036507
Smallest square containing exactly n decimal digits '0'.
Original entry on oeis.org
0, 100, 102400, 10000, 10240000, 1000000, 1024000000, 100000000, 102400000000, 10000000000, 10240000000000, 1000000000000, 1024000000000000, 100000000000000, 102400000000000000, 10000000000000000, 10240000000000000000, 1000000000000000000, 1024000000000000000000
Offset: 1
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nsmall = Table[Infinity, 20];
For[i = 0, i <= 4*10^6, i++, n0 = Count[IntegerDigits[i^2], 0];
If[nsmall[[n0]] > i^2, nsmall[[n0]] = i^2]];
ReplaceAll[nsmall, Infinity -> "?"] (* Robert Price, Mar 22 2020 *)
a[n_] := If[OddQ[n], 1024*10^(n-1), 10^n]; a[1] = 0; Array[a, 20] (* Amiram Eldar, Aug 26 2025 *)
A036534
Smallest cube containing exactly n 7's.
Original entry on oeis.org
0, 27, 17576, 571787, 5177717, 7797729087, 25750777177, 7707245470777, 744736797077707, 17373777757776999, 77777383297757779, 77077787864771842777, 2717772770751727979277, 74677779777959671778577, 787773477172377877676776, 77227778717777797207914717
Offset: 0
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nsmall = Table[Infinity, 20];
For[i = 0, i <= 10^6, i++, n0 = Count[IntegerDigits[i^3], 7];
If[nsmall[[n0 + 1]] > i^3, nsmall[[n0 + 1]] = i^3]];
Cases[nsmall, ?NumberQ] (* _Robert Price, Mar 21 2020 *)
A048352
a(n)^2 is the smallest square containing exactly n 7's.
Original entry on oeis.org
24, 76, 424, 3576, 8819, 88924, 278874, 2116076, 8819154, 61463576, 277450424, 526087234, 1943470576, 21858013924, 199694210926, 260341642412, 3574601764924, 11156736878576, 27180356468924, 275640849218286, 1130388343790654, 8818036509210958, 57251968301165924, 75972671255970576, 841288938282667412
Offset: 1
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a[n_] := Module[{i = 1}, While[DigitCount[i^2][[7]] != n, i++ ]; i]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 22 2006 *)
A137434
a(n) = smallest square containing n copies of the same nonzero digit.
Original entry on oeis.org
1, 121, 1444, 44944, 6441444, 47444544, 4434494464, 44424414441, 1113111511681, 22222220262025, 444431244445444, 22292262226224225, 441544444344443449, 1113101111111117041, 2222222222222640225, 11111119101145491111121
Offset: 1
a(9) = 1113111511681 because there is no smaller square number with 9 copies of the same nonzero digit. a(9) has 9 1's.
Showing 1-4 of 4 results.
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