A100790 First differences of A047780.
1, 9, 47, 183, 560, 1426, 3164, 6322, 11643, 20095, 32901, 51569, 77922, 114128, 162730, 226676, 309349, 414597, 546763, 710715, 911876, 1156254, 1450472, 1801798, 2218175, 2708251, 3281409, 3947797, 4718358, 5604860
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (6, -15, 20, -15, 6, -1).
Programs
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Mathematica
Differences[CoefficientList[Series[x (1+3x+8x^2+16x^3+2x^4)/(1-x)^7,{x,0,50}],x]] (* or *) LinearRecurrence[{6,-15,20,-15,6,-1},{1,9,47,183,560,1426},50] (* Harvey P. Dale, Dec 18 2013 *)
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PARI
a(n)=(n+1)(6*n^4+9*n^3+23*n^2+46*n+24)/24 \\ Charles R Greathouse IV, Oct 21 2022
Formula
(1/24)(n+1)(6n^4+9n^3+23n^2+46n+24). - Ralf Stephan, May 16 2007
a(0)=1, a(1)=9, a(2)=47, a(3)=183, a(4)=560, a(5)=1426, a(n)= 6*a(n-1)- 15*a(n-2)+ 20*a(n-3)-15*a(n-4)+6*a(n-5)-a(n-6). - Harvey P. Dale, Dec 18 2013
Comments