cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-4 of 4 results.

A030158 Even squares in which parity of digits alternates.

Original entry on oeis.org

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

Views

Author

Patrick De Geest

Keywords

Links

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

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

Original entry on oeis.org

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

Views

Author

Patrick De Geest

Keywords

Links

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 *)

A030156 Odd squares in which parity of digits alternates.

Original entry on oeis.org

1, 9, 25, 49, 81, 121, 169, 361, 529, 729, 961, 4761, 6561, 12321, 12769, 14161, 16129, 18769, 32761, 34969, 56169, 72361, 74529, 76729, 78961, 96721, 212521, 214369, 290521, 436921, 452929, 458329, 474721, 670761, 690561, 1038361
Offset: 1

Views

Author

Patrick De Geest

Keywords

Links

Crossrefs

Cf. A030151, A030152, A030155, A030157, A030158.

Programs

  • Mathematica
    altQ[n_] := n < 10 || Union[Total /@ Partition[ Mod[ IntegerDigits@n, 2], 2, 1]] == {1}; Select[ Range[1, 2000, 2]^2, altQ[#] &] (* Giovanni Resta, Aug 16 2018 *)

Extensions

Offset changed by Giovanni Resta, Aug 16 2018

A030155 Odd n such that in n^2 the parity of digits alternates.

Original entry on oeis.org

1, 3, 5, 7, 9, 11, 13, 19, 23, 27, 31, 69, 81, 111, 113, 119, 127, 137, 181, 187, 237, 269, 273, 277, 281, 311, 461, 463, 539, 661, 673, 677, 689, 819, 831, 1019, 1027, 1111, 1113, 1119, 1127, 1137, 1269, 1277, 1287, 1361, 1369, 1377, 1863, 1969
Offset: 1

Views

Author

Patrick De Geest

Keywords

Links

Crossrefs

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

Programs

  • Mathematica
    altQ[n_] := n < 10 || Union[Total /@ Partition[ Mod[ IntegerDigits@n, 2], 2, 1]] == {1}; Select[ Range[1, 2000, 2], altQ[#^2] &] (* Giovanni Resta, Aug 16 2018 *)

Extensions

Offset changed by Giovanni Resta, Aug 16 2018
Showing 1-4 of 4 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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