A018858 -id:A018858 - cp's OEIS frontend

A018857 Smallest power of 3 that begins with n.

1, 27, 3, 4782969, 59049, 6561, 729, 81, 9, 10460353203, 1162261467, 129140163, 1350851717672992089, 14348907, 1594323, 16677181699666569, 177147, 1853020188851841, 19683, 205891132094649, 2187, 22876792454961

Offset: 1

David W. Wilson

Seiichi Manyama, Table of n, a(n) for n = 1..563

Cf. A018802 (k=2), this sequence (k=3), A018859 (k=4), A018861 (k=5), A018863 (k=6), A018865 (k=7), A018867 (k=8), A018869 (k=9).

a(n) = 3^A018858(n). - Seiichi Manyama, Jan 29 2017

a(3^n) = 3^n for n >= 0. - Seiichi Manyama, Jan 29 2017

A018862 5^a(n) is smallest power of 5 beginning with n.

Original entry on oeis.org

0, 2, 5, 11, 1, 4, 7, 50, 10, 63, 23, 3, 56, 26, 6, 69, 49, 29, 9, 82, 62, 42, 22, 12, 2, 75, 55, 45, 25, 15, 5, 88, 68, 58, 48, 38, 28, 18, 8, 91, 81, 71, 61, 51, 41, 31, 21, 11, 104, 94, 84, 74, 167, 64, 54, 44, 137, 34, 24, 117, 14, 4, 97, 87, 180, 77, 67, 160, 57, 150, 47, 37, 130

Offset: 1

David W. Wilson

D. Mondot, Table of n, a(n) for n=1..32699

Cf. A018861.

Cf. A018858, A018860, A018864, A018866, A018868, A062525, A062526.

a(n) = my(k=0, ss=Str(n)); while(strsplit(Str(5^k), ss)[1] != "", k++); k; \\ Michel Marcus, Aug 19 2025

A374922 a(n) is the least k such that 3^k begins with n!.

Original entry on oeis.org

0, 0, 3, 8, 5, 805, 1689, 12317, 197209, 520852, 4493819, 16769097, 2053077332, 1110380591, 39230711849, 516641987008, 62653098988435, 398166000236882, 7896283077809532, 99956735615338266, 5161719458617927763, 63295038588725505792, 659220983938327840981

Offset: 0

Zhining Yang, Jul 23 2024

			a(4) = 5 because 3^5 = 243 is the smallest power of 3 beginning with 4! = 24.

Zhao Hui Du, Table of n, a(n) for n = 0..100

Cf. A018858, A000142, A374923.

a[n_] := Module[{target = IntegerDigits[n!], k = 0},
   While[UnsameQ[Take[IntegerDigits[3^k], Length@target], target],
    k++]; k];
Table[a[n], {n, 0, 8}]

a(n) = A018858(n!).

a(13) onwards from Zhao Hui Du, Oct 03 2024

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A018857 Smallest power of 3 that begins with n.

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A018862 5^a(n) is smallest power of 5 beginning with n.

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A374922 a(n) is the least k such that 3^k begins with n!.

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