login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A275574 ((-1)^n - 1 + 2*(n^floor((n + 1)/2)))/4 2
0, 1, 4, 8, 62, 108, 1200, 2048, 29524, 50000, 885780, 1492992, 31374258, 52706752, 1281445312, 2147483648, 59293938248, 99179645184, 3065533128900, 5120000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Number of 2-r stable discrete function classes on [n] under reversal and complement to n+1.

f(n) == 2 (mod 4) if n == 5 mod 8, otherwise (except for n=2) f(n) == 0 (mod 4). - Robert Israel, Aug 09 2016

LINKS

Robert Israel, Table of n, a(n) for n = 1..700

MAPLE

f:= n -> ((-1)^n - 1 + 2*(n^floor((n + 1)/2)))/4:

map(f, [$1..30]); # Robert Israel, Aug 09 2016

MATHEMATICA

Table[1/4 ((-1)^ n-1+2 (n)^Floor[(n+1)/2]), {n, 1, 20}]

CROSSREFS

Cf. A275550.

Sequence in context: A269998 A335527 A303284 * A214590 A215713 A120777

Adjacent sequences:  A275571 A275572 A275573 * A275575 A275576 A275577

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard, Aug 02 2016

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 24 20:34 EST 2020. Contains 338616 sequences. (Running on oeis4.)