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A226016 Primes with alternate digits even and odd, and most significant digit even. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The only difference compared to A068887 is that the 3 is missing here. - R. J. Mathar, May 26 2013
LINKS
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
Sequence in context: A154758 A156614 A355430 * A235150 A114549 A235148
KEYWORD
nonn,base
AUTHOR
Jayanta Basu, May 22 2013
STATUS
approved

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Last modified March 28 13:42 EDT 2024. Contains 371254 sequences. (Running on oeis4.)