A030158 Even squares in which parity of digits alternates.

0, 4, 16, 36, 256, 676, 1296, 5476, 7056, 9216, 41616, 69696, 87616, 147456, 163216, 181476, 329476, 341056, 367236, 527076, 541696, 583696, 763876, 781456, 929296, 2143296, 2509056, 2547216, 2903616, 4145296, 4301476

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Links

• Giovanni Resta, Table of n, a(n) for n = 1..10000 (First 359 terms from Vincenzo Librandi)

Crossrefs

Cf. A030157.

Programs

Mathematica

Join[{0, 4}, id[n_]:=IntegerDigits[n^2]; t={}; Do[If[Length[id[n]]==1, AppendTo[t, n], If[Union[Abs[Differences[Boole/@EvenQ[id[n]]]]]=={1}, AppendTo[t, n^2]]], {n, 4, 6000, 2}]; t] (* Vincenzo Librandi, Aug 15 2018 *)

Formula

a(n) = A030157(n)^2. - Michel Marcus, Aug 15 2018

Extensions

Offset changed by Michel Marcus, Aug 15 2018