OFFSET
0,4
COMMENTS
Without initial zeros, Molien series for 3-dimensional group [2+,n] = 2*(n/2).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..5000
Index entries for linear recurrences with constant coefficients, signature (2,-1,0,0,1,-2,1).
FORMULA
G.f.: x^2*(1+x^3)/((1-x)^2*(1-x^5)) = x^2*(1+x)*(1-x+x^2)/( (1-x)^3 *(1+x+x^2+x^3+x^4) ).
MATHEMATICA
Floor[(Range[0, 60]^2 + 1)/5] (* G. C. Greubel, Aug 03 2019 *)
PROG
(PARI) a(n)=(n^2+1)\5;
(Magma) [(n^2+1) div 5: n in [0..60]]; // Bruno Berselli, Oct 28 2011
(Sage) [floor((n^2+1)/5) for n in (0..60)] # G. C. Greubel, Aug 03 2019
(GAP) List([0..60], n-> Int((n^2 + 1)/5)); # G. C. Greubel, Aug 03 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Philip Mummert (s1280900(AT)cedarville.edu), May 10 2000
STATUS
approved