A045926 All digits even and nonzero.

2, 4, 6, 8, 22, 24, 26, 28, 42, 44, 46, 48, 62, 64, 66, 68, 82, 84, 86, 88, 222, 224, 226, 228, 242, 244, 246, 248, 262, 264, 266, 268, 282, 284, 286, 288, 422, 424, 426, 428, 442, 444, 446, 448, 462, 464, 466, 468, 482, 484, 486, 488, 622, 624, 626, 628, 642

Offset: 1

Author

Felice Russo

Keywords

• nonn
• easy
• base

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• Index entries for 10-automatic sequences.

Crossrefs

Cf. A045927, A014261, A014263, A192370.

Programs

Haskell

a045926 n = a045926_list !! (n-1)
a045926_list = filter (all (`elem` "2468") . show) [2, 4..]
-- Reinhard Zumkeller, Jan 01 2013

Python

def A045926(n):
    m = (3*n+1).bit_length()-1>>1
    return int(''.join((str(((3*n+1-(1<<(m<<1)))//(3<<((m-1-j)<<1))&3)+1) for j in range(m))))<<1 # Chai Wah Wu, Feb 08 2023

Formula

a(n) = 2 * A084544(n). - Reinhard Zumkeller, Jan 01 2013

Extensions

More terms from Patrick De Geest, Jun 15 1999