A018860 -id:A018860 - cp's OEIS frontend

A018859 Smallest power of 4 that begins with n.

1, 256, 302231454903657293676544, 4, 5070602400912917605986812821504, 64, 70368744177664, 81129638414606681695789005144064, 91343852333181432387730302044767688728495783936, 1024, 1125899906842624

Offset: 1

David W. Wilson

Seiichi Manyama, Table of n, a(n) for n = 1..490

Cf. A018802 (k=2), A018857 (k=3), this sequence (k=4), A018861 (k=5), A018863 (k=6), A018865 (k=7), A018867 (k=8), A018869 (k=9).

a(n) = 4^A018860(n). - Michel Marcus, Feb 24 2016

a(4^n) = 4^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

cp's OEIS Frontend

A018859 Smallest power of 4 that begins with n.

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