OFFSET
0,2
COMMENTS
7 times 7-gonal numbers.
LINKS
Ivan Panchenko, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = (35*n^2 - 21*n)/2 = A000566(n)*7.
a(n) = a(n-1)+35*n-28 (with a(0)=0). - Vincenzo Librandi, Dec 15 2010
MAPLE
MATHEMATICA
s=0; lst={s}; Do[s+=n; AppendTo[lst, s], {n, 7, 8!, 35}]; lst (* Vladimir Joseph Stephan Orlovsky, Apr 03 2009 *)
7*PolygonalNumber[7, Range[0, 40]] (* Harvey P. Dale, Jun 03 2024 *)
PROG
(Magma) [ 7*n*(5*n-3)/2 : n in [0..50] ]; // Wesley Ivan Hurt, Jun 09 2014
(PARI) a(n)=7*n*(5*n-3)/2 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Omar E. Pol, Dec 13 2008
STATUS
approved