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 A266561 12-dimensional square numbers. 1
 1, 14, 104, 546, 2275, 8008, 24752, 68952, 176358, 419900, 940576, 1998724, 4056234, 7904456, 14858000, 27041560, 47805615, 82317690, 138389160, 227613750, 366913365, 580610160, 903171360, 1382805840, 2086129500, 3104160696, 4559958144, 6618272584 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS 2*a(n) is number of ways to place 11 queens on an (n+11) X (n+11) chessboard so that they diagonally attack each other exactly 55 times. The maximal possible attack number, p=binomial(k,2)=55 for k=11 queens, is achievable only when all queens are on the same diagonal. In graph-theory representation they thus form the corresponding complete graph. LINKS Table of n, a(n) for n=0..27. OEIS Wiki, Square hyperpyramidal numbers, line d=12 of first table. FORMULA a(n) = binomial(n+11,11)*(n+6)/6. a(n) = 2*binomial(n+12,12) - binomial(n+11,11). a(n) = binomial(n+11,11) + 2*binomial(n+11,12) for n>0. G.f.: (1+x)/(1-x)^13. - Vincenzo Librandi, Jan 01 2016 MATHEMATICA CoefficientList[Series[(1 + x)/(1 - x)^13, {x, 0, 33}], x] (* Vincenzo Librandi, Jan 01 2016 *) PROG (Magma) [Binomial(n+11, 11)*(n+6)/6: n in [0..40]]; // Vincenzo Librandi, Jan 01 2016 CROSSREFS Cf. A000330, A002415, A005585, A040977, A050486, A053347, A054333, A054334, A057788. Sequence in context: A161475 A162301 A161862 * A370962 A222369 A131709 Adjacent sequences: A266558 A266559 A266560 * A266562 A266563 A266564 KEYWORD nonn,easy AUTHOR Antal Pinter, Dec 31 2015 STATUS approved

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Last modified September 16 14:26 EDT 2024. Contains 375976 sequences. (Running on oeis4.)