This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A152744 7 times pentagonal numbers: 7n(3n-1)/2. 3
 0, 7, 35, 84, 154, 245, 357, 490, 644, 819, 1015, 1232, 1470, 1729, 2009, 2310, 2632, 2975, 3339, 3724, 4130, 4557, 5005, 5474, 5964, 6475, 7007, 7560, 8134, 8729, 9345, 9982, 10640, 11319, 12019, 12740, 13482, 14245, 15029 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 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) = (21n^2 - 7n)/2 = A000326(n)*7. a(n) = a(n-1)+21*n-14 (with a(0)=0). - Vincenzo Librandi, Nov 26 2010 G.f.: 7*x*(1+2*x)/(1-x)^3. - Colin Barker, Feb 14 2012 a(0)=0, a(1)=7, a(2)=35, a(n)=3*a(n-1)-3*a(n-2)+a(n-3). - Harvey P. Dale, Aug 08 2013 MATHEMATICA s=0; lst={s}; Do[s+=n; AppendTo[lst, s], {n, 7, 7!, 21}]; lst (* Vladimir Joseph Stephan Orlovsky, Apr 03 2009 *) Table[7n (3n-1)/2, {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 7, 35}, 50] (* Harvey P. Dale, Aug 08 2013 *) PROG (PARI) a(n)=7*n*(3*n-1)/2 \\ Charles R Greathouse IV, Jun 17 2017 CROSSREFS Cf. A000326, A014642, A152743. Sequence in context: A061825 A077536 A256391 * A169607 A130884 A037092 Adjacent sequences:  A152741 A152742 A152743 * A152745 A152746 A152747 KEYWORD easy,nonn AUTHOR Omar E. Pol, Dec 12 2008 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.