A102251 Begin with 1, multiply each digit by 2.

1, 2, 4, 8, 16, 2, 12, 4, 2, 4, 8, 4, 8, 16, 8, 16, 2, 12, 16, 2, 12, 4, 2, 4, 2, 12, 4, 2, 4, 8, 4, 8, 4, 2, 4, 8, 4, 8, 16, 8, 16, 8, 4, 8, 16, 8, 16, 2, 12, 16, 2, 12, 16, 8, 16, 2, 12, 16, 2, 12, 4, 2, 4, 2, 12, 4, 2, 4, 2, 12, 16, 2, 12, 4, 2, 4, 2, 12, 4, 2, 4, 8, 4, 8, 4, 2, 4, 8, 4, 8, 4, 2, 4

Offset: 0

Author

Alexandre Wajnberg and Eric Angelini, Feb 18 2005

Keywords

• base
• easy
• nonn

Comments

Same digits as A061581 without the memory of the groupings of the preceding digits. A bunch of sequences can be produced with this rule: a(n)=d*k beginning with 1,2,3... for k=2,3,...

Examples

			Read a(5)=16 which produces a(6)=2 because 1*2=2 and a(7)=12 because 6*2=12. Now read a(6)=2 which produces [a(7) is already written] a(8)=4 because 2*2=4.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A061581.

Cf. A248131.

Programs

Haskell

a102251 n = a102251_list !! n
a102251_list = 1 : (map (* 2) $
               concatMap (map (read . return) . show) a102251_list)
-- Reinhard Zumkeller, Oct 02 2014

Mathematica

Flatten[ NestList[ Function[x, Flatten[ FromDigits /@ 2IntegerDigits[ x]]], 1, 15]] (* Robert G. Wilson v, Feb 21 2005 *)

Formula

d*2, beginning with 1

Extensions

More terms from Robert G. Wilson v, Feb 21 2005