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A002797
Number of solutions to a linear inequality.
(Formerly M1360 N0524)
1
3, 2, 5, 9, 17, 27, 40, 55, 73, 94, 117, 143, 171, 203, 236, 273, 311, 354, 397, 445, 493, 547, 600, 659, 717, 782, 845, 915, 983, 1059, 1132, 1213, 1291, 1378, 1461, 1553, 1641, 1739, 1832, 1935, 2033, 2142, 2245, 2359, 2467, 2587, 2700
OFFSET
0,1
REFERENCES
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
E. Ehrhart, Sur un problème de géométrie diophantienne linéaire I, (Polyèdres et réseaux), J. Reine Angew. Math. 226 1967 1-29. MR0213320 (35 #4184). [Annotated scanned copy of pages 16 and 22 only]
E. Ehrhart, Sur un problème de géométrie diophantienne linéaire II. Systemes diophantiens lineaires, J. Reine Angew. Math. 227 1967 25-49. [Annotated scanned copy of pages 47-49 only]
FORMULA
a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-4) - a(n-5) - a(n-6) + a(n-7). - Sean A. Irvine, Aug 20 2014
G.f.: -(5*x^6+7*x^5+2*x^4+5*x^3-x+3)/((x^2+1)*(x+1)^2*(x-1)^3). - Alois P. Heinz, Aug 20 2014
PROG
(PARI) Vec(-(5*x^6+7*x^5+2*x^4+5*x^3-x+3)/((x^2+1)*(x+1)^2*(x-1)^3) + O(x^50)) \\ Michel Marcus, Jan 26 2015
CROSSREFS
Sequence in context: A193796 A249906 A258930 * A049920 A257981 A128914
KEYWORD
nonn,easy
EXTENSIONS
Initial term, missing a(9), and more terms from Sean A. Irvine, Aug 20 2014
STATUS
approved