A004093 Even numbers written backwards.

0, 2, 4, 6, 8, 1, 21, 41, 61, 81, 2, 22, 42, 62, 82, 3, 23, 43, 63, 83, 4, 24, 44, 64, 84, 5, 25, 45, 65, 85, 6, 26, 46, 66, 86, 7, 27, 47, 67, 87, 8, 28, 48, 68, 88, 9, 29, 49, 69, 89, 1, 201, 401, 601, 801, 11, 211, 411, 611, 811, 21, 221, 421, 621, 821, 31

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• base
• look

Links

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

Crossrefs

Cf. A004086.

Programs

Haskell

a004093 = a004086 . (* 2)  -- Reinhard Zumkeller, Feb 09 2012

PARI

a(n) = fromdigits(Vecrev(digits(2*n))); \\ Michel Marcus, Nov 14 2022

Python

def a(n): return int(str(2*n)[::-1])
print([a(n) for n in range(66)]) # Michael S. Branicky, Nov 14 2022

Formula

a(n) = A004086(2*n). - Reinhard Zumkeller, Feb 09 2012