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.

A117870 Square board sizes for which the lights out problem does not have a unique solution (counting solutions differing only by rotation and reflection as distinct).

Original entry on oeis.org

4, 5, 9, 11, 14, 16, 17, 19, 23, 24, 29, 30, 32, 33, 34, 35, 39, 41, 44, 47, 49, 50, 53, 54, 59, 61, 62, 64, 65, 67, 69, 71, 74, 77, 79, 83, 84, 89, 92, 94, 95, 98, 99, 101, 104, 107, 109, 113, 114, 118, 119, 123, 124, 125, 126, 128, 129, 131, 134, 135, 137, 139, 143
Offset: 1

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Author

N. J. A. Sloane, May 14 2006

Keywords

Comments

Numbers k such that a k X k parity pattern exists (see A118141). - Don Knuth, May 11 2006

Crossrefs

Cf. A075462, A076437, A117872. Complement of A076436.

Formula

a(n) = A093614(n) - 1.
Contains positive integers k such that A159257(k) > 0. - Max Alekseyev, Sep 17 2009

Extensions

More terms from Max Alekseyev, Sep 17 2009, and Thomas Buchholz, May 16 2014