The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A017054 a(n) = (7*n + 6)^2. 1
 36, 169, 400, 729, 1156, 1681, 2304, 3025, 3844, 4761, 5776, 6889, 8100, 9409, 10816, 12321, 13924, 15625, 17424, 19321, 21316, 23409, 25600, 27889, 30276, 32761, 35344, 38025, 40804, 43681, 46656 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS If Y is a fixed 2-subset of a (7n+1)-set X then a(n-1) is the number of 3-subsets of X intersecting Y. - Milan Janjic, Oct 21 2007 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..10000 Milan Janjic, Two Enumerative Functions Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3); a(0)=36, a(1)=169, a(2)=400. - Harvey P. Dale, Apr 28 2016 MATHEMATICA (7*Range[0, 30]+6)^2 (* or *) LinearRecurrence[{3, -3, 1}, {36, 169, 400}, 40] (* Harvey P. Dale, Apr 28 2016 *) PROG (MAGMA) [(7*n+6)^2: n in [0..40]]; // Vincenzo Librandi, Jul 10 2011 (PARI) a(n)=(7*n+6)^2 \\ Charles R Greathouse IV, Jun 17 2017 CROSSREFS Cf. A017053 (7*n+6). Sequence in context: A264474 A338390 A268905 * A231972 A330770 A166708 Adjacent sequences:  A017051 A017052 A017053 * A017055 A017056 A017057 KEYWORD nonn,easy AUTHOR 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 8 20:32 EDT 2021. Contains 343668 sequences. (Running on oeis4.)