A030143 Even numbers in which parity of digits alternates.

0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 30, 32, 34, 36, 38, 50, 52, 54, 56, 58, 70, 72, 74, 76, 78, 90, 92, 94, 96, 98, 210, 212, 214, 216, 218, 230, 232, 234, 236, 238, 250, 252, 254, 256, 258, 270, 272, 274, 276, 278, 290, 292, 294, 296, 298, 410, 412, 414

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base
• easy

Links

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

Crossrefs

Cf. A030142, A062285, intersection of A005843 and A030141.

Programs

Haskell

a030143 n = a030143_list !! (n-1)
a030143_list = filter even a030141_list
-- Reinhard Zumkeller, Aug 31 2013

Mathematica

id[n_]:=IntegerDigits[n]; t={}; Do[If[Length[id[n]]==1, AppendTo[t,n],If[Union[Abs[Differences[Boole /@ EvenQ[id[n]]]]]=={1}, AppendTo[t,n]]], {n,0,414,2}]; t (* Jayanta Basu, May 07 2013 *)

Formula

(1 - a(n) mod 2) * A228710(a(n)) = 1. - Reinhard Zumkeller, Aug 31 2013

Extensions

Offset corrected by Reinhard Zumkeller, Aug 31 2013