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

1,1

Comments

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

Links

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

Example

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

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 *)

Crossrefs

Cf. A000040, A030144.

Sequence in context: A154758 A156614 A355430 * A235150 A114549 A235148

Adjacent sequences: A226013 A226014 A226015 * A226017 A226018 A226019

Keyword

nonn,base

Author

Jayanta Basu, May 22 2013

Status

approved