A092539 Binary representation of a(n) equals first n+1 terms of A051023.

1, 3, 6, 13, 27, 55, 110, 220, 441, 883, 1766, 3532, 7064, 14129, 28258, 56517, 113035, 226070, 452140, 904281, 1808562, 3617124, 7234249, 14468499, 28936999, 57873998, 115747997, 231495994, 462991989, 925983979, 1851967959, 3703935918

Offset: 0

Author

Zak Seidov, Feb 27 2004

Keywords

• easy
• nonn

Comments

a(n+1) = 2*a(n) + d, where d = 0/1 with no obvious rule. The sequence is a digit representation of the central column of cellular automaton Rule 30, A051023. Primes in the sequence, A092540.

Examples

			a(6) = 55_10 = 110111_2
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..1000
• Eric Weisstein's World of Mathematics, Rule 30.

Crossrefs

Cf. A051023, A092540.

Programs

Haskell

a092539 n = a092539_list !! n
a092539_list = scanl1 (\v d -> 2 * v + d) $ map toInteger a051023_list
-- Reinhard Zumkeller, Jun 08 2013

Mathematica

a(n_) := FromDigits[Take[A051023, n], 2]

Formula

a(n+1) = 2*a(n) + A051023(n+1). - Reinhard Zumkeller, Jun 08 2013

Extensions

Offset corrected and definition adjusted by Reinhard Zumkeller, Jun 08 2013