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 A062027 a(1) = a(2) = a(3) = 1; and for n>3 a(n) = 1*2*3*4 + 2*3*4*5 + 3*4*5*6 + ... + (n-1)*n*1*2 + n*1*2*3, the sum of the cyclic product of terms taken four at a time, final term being n*1*2*3 = 6n. 2
 1, 1, 1, 96, 274, 720, 1680, 3520, 6750, 12048, 20284, 32544, 50154, 74704, 108072, 152448, 210358, 284688, 378708, 496096, 640962, 817872, 1031872, 1288512, 1593870, 1954576, 2377836, 2871456, 3443866, 4104144, 4862040, 5728000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Harry J. Smith, Table of n, a(n) for n=1,...,1000 FORMULA a(n) = (n+1)(n)(n-1)(n-2)(n-3)/5 + n(n^2 -n +6). EXAMPLE a(5) = 1*2*3*4 + 2*3*4*5 + 3*4*5*1 + 4*5*1*2 + 5*1*2*3 = 274. PROG (PARI) { a=1; for (n=1, 1000, if (n>3, a=(n + 1)*n*(n - 1)*(n - 2)*(n - 3)/5 + n*(n^2 - n + 6)); write("b062027.txt", n, " ", a) ) } \\ Harry J. Smith, Jul 30 2009 CROSSREFS Sequence in context: A232939 A202591 A202584 * A320883 A048189 A304830 Adjacent sequences:  A062024 A062025 A062026 * A062028 A062029 A062030 KEYWORD nonn AUTHOR Amarnath Murthy, Jun 02 2001 EXTENSIONS More terms from Jason Earls, Jun 07 2001 Term a(4) corrected by Harry J. Smith, Jul 30 2009 STATUS approved

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Last modified February 28 11:08 EST 2020. Contains 332323 sequences. (Running on oeis4.)