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 A274973 Centered cubohemioctahedral numbers: a(n) = 2*n^3+9*n^2+n+1. 2
 1, 13, 55, 139, 277, 481, 763, 1135, 1609, 2197, 2911, 3763, 4765, 5929, 7267, 8791, 10513, 12445, 14599, 16987, 19621, 22513, 25675, 29119, 32857, 36901, 41263, 45955, 50989, 56377, 62131, 68263, 74785, 81709, 89047, 96811, 105013, 113665, 122779, 132367 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS A faceting of the cuboctahedron, sharing the same square faces. The cubohemioctahedron has the same edge and vertex arrangement as the cuboctahedron.  Beginning with the fourth term, the eight tetrahedral faces are each now "missing" a tetrahedron of size 1,4,10,20,35...(A000292). See A274974 centered octahemioctahedron for similar cuboctahedral faceting but with the square faces "missing." LINKS Wikipedia, Cubohemioctahedron Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1). FORMULA a(n) = 2*n^3+9*n^2+n+1. G.f.: (-7*x^3+9*x^2+9*x+1)/(x-1)^4. MATHEMATICA Table[2 n^3 + 9 n^2 + n + 1, {n, 40}] (* Michael De Vlieger, Jul 13 2016 *) PROG (PARI) a(n)=2*n^3+9*n^2+n+1 \\ Charles R Greathouse IV, Jul 14 2016 CROSSREFS Cf. A005902 (centered cuboctahedral numbers), A274974 (centered octahemioctahedral numbers). Sequence in context: A198160 A029531 A158485 * A005902 A051798 A206372 Adjacent sequences:  A274970 A274971 A274972 * A274974 A274975 A274976 KEYWORD nonn,easy AUTHOR Steven Beard, Jul 13 2016 STATUS approved

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Last modified January 24 19:12 EST 2021. Contains 340411 sequences. (Running on oeis4.)