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

0,2

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,...

Links

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

Formula

d*2, beginning with 1

Example

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.

Mathematica

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

Prog

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

Crossrefs

Cf. A061581.

Cf. A248131.

Sequence in context: A110333 A247292 A069783 * A339853 A373944 A218338

Adjacent sequences: A102248 A102249 A102250 * A102252 A102253 A102254

Keyword

base,easy,nonn

Author

Alexandre Wajnberg and Eric Angelini, Feb 18 2005

Extensions

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

Status

approved