A226016 Primes with alternate digits even and odd, and most significant digit even.

2, 23, 29, 41, 43, 47, 61, 67, 83, 89, 2129, 2141, 2143, 2161, 2309, 2341, 2347, 2381, 2383, 2389, 2503, 2521, 2543, 2549, 2707, 2729, 2741, 2749, 2767, 2789, 2903, 2909, 2927, 2963, 2969, 4127, 4129, 4327, 4349, 4363, 4507, 4523, 4547, 4549, 4561, 4567, 4583

Offset: 1

Author

Jayanta Basu, May 22 2013

Keywords

• nonn
• base

Comments

The only difference compared to A068887 is that the 3 is missing here. - R. J. Mathar, May 26 2013

Examples

			2143 is a member since its digits are alternatively even and odd.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..2000

Crossrefs

Cf. A000040, A030144.

Programs

Mathematica

a[n_,k_]:=Union[Boole/@EvenQ[Take[IntegerDigits[n],{k,-1,2}]]]; Join[{2},Select[Prime[Range[5,620]],{a[#,1],a[#,2]}=={{1},{0}} &]]
Select[Prime[Range[1000]],Boole[EvenQ[IntegerDigits[#]]]==PadRight[{},IntegerLength[#],{1,0}]&] (* Harvey P. Dale, Oct 28 2023 *)