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 *)
A048351
a(n)^2 is the smallest square containing exactly n 6's.
Original entry on oeis.org
4, 26, 216, 1291, 5164, 68313, 163284, 785294, 3559026, 26393686, 129099069, 254296413, 816435342, 4081257976, 80413106314, 215329205326, 2463064689907, 5165911014784, 24832773982716, 81401883640163, 752766125152206, 4086159158264236, 21602469586893686, 32659863237109026, 683788466294121304
Offset: 1
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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 *)
-
def a(n):
k = 1
while not str(k**2).count('6') == n: k += 1
return k
print([a(n) for n in range(1, 11)]) # Michael S. Branicky, Apr 26 2021
a(13) from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 20 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 1-3 of 3 results.