|
|
A000703
|
|
Chromatic number (or Heawood number) of nonorientable surface with n crosscaps.
(Formerly M3265 N1318)
|
|
3
|
|
|
4, 6, 7, 7, 8, 9, 9, 10, 10, 10, 11, 11, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 18, 19, 19, 19, 19, 19, 19, 20, 20, 20, 20, 20, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
REFERENCES
|
J. L. Gross and T. W. Tucker, Topological Graph Theory, Wiley, 1987; see Table 5.2 p. 221.
J. L. Gross and J. Yellen, eds., Handbook of Graph Theory, CRC Press, 2004; p. 368 and 631.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
|
|
LINKS
|
|
|
FORMULA
|
a(n) = floor((7+sqrt(1+24*n))/2).
|
|
MAPLE
|
|
|
MATHEMATICA
|
Floor[(7+Sqrt[1+24*Range[0, 80]])/2] (* Harvey P. Dale, Feb 03 2012 *)
|
|
PROG
|
(Haskell)
a000703 = floor . (/ 2) . (+ 7) . sqrt . (+ 1) . (* 24) . fromInteger
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,nice,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|