A030145 Primes such that in p^2 the parity of digits alternates.

2, 3, 5, 7, 11, 13, 19, 23, 31, 113, 127, 137, 181, 269, 277, 281, 311, 461, 463, 661, 673, 677, 1019, 1277, 1361, 1973, 2287, 2339, 2377, 2411, 2423, 2689, 2731, 4673, 5023, 5081, 5261, 6563, 6577, 8311, 9013, 9437, 9439, 10181, 10463

Offset

1,1

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000

Formula

a(n)^2 = A030146(n). - Giovanni Resta, Aug 16 2018

Mathematica

id[n_]:=IntegerDigits[n]; t={}; Do[p=Prime[n]; If[Length[id[p]]==1, AppendTo[t, p], If[Union[Abs[Differences[Boole/@EvenQ[id[p^2]]]]]=={1}, AppendTo[t, p]]], {n, 1300}]; t (* Jayanta Basu, May 07 2013 *)
pdaQ[n_]:=FreeQ[Differences[Boole[EvenQ[IntegerDigits[n^2]]]], 0]; Select[ Prime[ Range[1300]], pdaQ] (* Harvey P. Dale, Jul 30 2019 *)

Crossrefs

Cf. A030144, A030146, A030151.

Sequence in context: A362527 A130807 A338577 * A285983 A020588 A227202

Adjacent sequences: A030142 A030143 A030144 * A030146 A030147 A030148

Keyword

nonn,base

Author

Patrick De Geest

Extensions

Offset corrected by Giovanni Resta, Aug 16 2018

Status

approved