A066107 - OEIS

%I #16 Feb 03 2020 15:27:28

%S 0,3,6,15,10,35,14,63,18,99,22,143,26,195,30,255,34,323,38,399,42,483,

%T 46,575,50,675,54,783,58,899,62,1023,66,1155,70,1295,74,1443,78,1599,

%U 82,1763,86,1935,90,2115,94,2303,98,2499,102,2703,106,2915,110,3135

%N a(0) = 0; for n > 0, a(2n+1) = (2n+1)*(2n+3); a(2n) = 2n + 2.

%H Harry J. Smith, <a href="/A066107/b066107.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,3,0,-3,0,1).

%F O.g.f.: (3x+6x^2+6x^3-8x^4-x^5+2x^6)/(1-x^2)^3. - _Len Smiley_, Dec 06 2001

%t LinearRecurrence[{0,3,0,-3,0,1},{0,3,6,15,10,35,14},60] (* _Harvey P. Dale_, Mar 14 2018 *)

%o (PARI) a(n) = polcoeff((3*x+6*x^2+6*x^3-8*x^4-x^5+2*x^6)/(1-x^2)^3+x*O(x^n),n) for(n=0,100,print1(a(n),","))

%o (PARI) { for (n=0, 1000, if(n==0, a=0, if(n%2, a=n*(n + 2), a=2*n+2)); write("b066107.txt", n, " ", a) ) } \\ _Harry J. Smith_, Nov 15 2009

%K easy,nonn

%O 0,2

%A _George E. Antoniou_, Dec 05 2001