A063565 Smallest positive number k such that 2^k contains n.

10, 4, 1, 5, 2, 8, 4, 15, 3, 12, 10, 40, 7, 17, 18, 21, 4, 27, 30, 13, 11, 18, 43, 41, 10, 8, 18, 15, 7, 32, 22, 17, 5, 25, 27, 25, 16, 30, 14, 42, 12, 22, 19, 22, 18, 28, 42, 31, 11, 32, 52, 9, 19, 16, 25, 16, 8, 20, 33, 33, 23, 58, 18, 14, 6, 16, 46, 24, 15, 34, 29, 21, 17, 30

Offset

0,1

Links

Chai Wah Wu, Table of n, a(n) for n = 0..10000

Popular Computing (Calabasas, CA), Two Tables, Vol. 1, (No. 9, Dec 1973), page PC9-16.

Example

a(7) = 15 because 2^15 = 32768.

Mathematica

a = {}; Do[k = 1; While[ StringPosition[ ToString[2^k], ToString[n] ] == {}, k++ ]; a = Append[a, k], {n, 0, 50} ]; a

Prog

(Python)
def A063565(n):
....s, k, k2 = str(n), 1, 2
....while True:
........if s in str(k2):
............return k
........k += 1
........k2 *= 2 # Chai Wah Wu, Jun 20 2015

Crossrefs

Apart from initial term, a duplicate of A030000.

Cf. A006889, A131535, A131536, A259089, A063565, A259091, A259092.

Sequence in context: A089478 A028967 A097530 * A371918 A177390 A082961

Adjacent sequences: A063562 A063563 A063564 * A063566 A063567 A063568

Keyword

base,nonn

Author

Robert G. Wilson v, Aug 10 2001

Extensions

More terms from Hans Havermann

Status

approved