A180392 Number of permutations of 1..n with both permutation and its inverse having exactly 2 maxima.

0, 0, 1, 12, 66, 248, 739, 1880, 4260, 8832, 17061, 31108, 54054, 90168, 145223, 226864

Offset

1,4

Links

Table of n, a(n) for n=1..16.

Crossrefs

Sequence in context: A271870 A114243 A000972 * A161805 A036399 A003200

Adjacent sequences: A180389 A180390 A180391 * A180393 A180394 A180395

Keyword

nonn

Author

R. H. Hardin, Sep 01 2010

Status

approved