A331619 a(n) is the smallest positive number k such that the decimal expansion of n*2^k contains the string n.

1, 4, 4, 7, 4, 9, 4, 8, 4, 10, 10, 10, 10, 10, 10, 10, 10, 7, 10, 10, 4, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 4, 10, 28, 19, 13, 15, 16, 40, 20, 30, 53, 27, 20, 27, 35, 30, 20, 53, 31, 20, 4, 8, 18, 35, 20, 10, 30, 23, 20

Offset

0,2

Links

Table of n, a(n) for n=0..68.

Rémy Sigrist, PARI program for A331619

Example

  n   a(n)  n*2^a(n)
  --  ----  --------
   0     1         0
   1     4        16
   2     4        32
   3     7       384
   4     4        64
   5     9      2560
   6     4        96
   7     8      1792
   8     4       128
   9    10      9216
  10    10     10240

Crossrefs

Cf. A030000, A331440.

Sequence in context: A197009 A204156 A163106 * A258972 A146564 A048785

Adjacent sequences: A331616 A331617 A331618 * A331620 A331621 A331622

Keyword

nonn,base

Author

Rémy Sigrist, Jan 22 2020

Status

approved