A030153 Numbers k such that in k and k^2 the parity of digits alternates.

0, 1, 2, 3, 4, 5, 6, 7, 9, 16, 23, 27, 36, 69, 74, 81, 96, 127, 181, 187, 296, 874, 2327, 2369, 2723, 2727, 2763, 3816, 4589, 5874, 6563, 6589, 6727, 8323, 10181, 12723, 18163, 18587, 21236, 21274, 29236, 29274, 30127, 43296, 52361, 78163, 87616

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Links

• Giovanni Resta, Table of n, a(n) for n = 1..1226 (derived from A030154 b-file)

Crossrefs

Cf. A030151, A030152, A030154, A030156, A030157, A030158.

Programs

Mathematica

altQ[n_] := n < 10 || Union[Total /@ Partition[ Mod[ IntegerDigits@n, 2], 2, 1]] == {1}; Select[ Range[0, 10^5], altQ[#] && altQ[#^2] &] (* Giovanni Resta, Aug 16 2018 *)