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 A060888 a(n) = n^6 - n^5 + n^4 - n^3 + n^2 - n + 1. 6
 1, 1, 43, 547, 3277, 13021, 39991, 102943, 233017, 478297, 909091, 1623931, 2756293, 4482037, 7027567, 10678711, 15790321, 22796593, 32222107, 44693587, 60952381, 81867661, 108450343, 141867727, 183458857, 234750601, 297474451 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS a(n) = Phi_14(n) where Phi_k is the k-th cyclotomic polynomial. Number of walks of length 7 between any two distinct nodes of the complete graph K_{n+1} (n>=1). - Emeric Deutsch, Apr 01 2004 For odd n, a(n) * (n+1) / 2 also represents the first integer in a sum of n^7 consecutive integers that equals n^14. - Patrick J. McNab, Dec 26 2016 LINKS Harry J. Smith, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (7, -21, 35, -35, 21, -7, 1). FORMULA G.f.: (1 - 6x + 57x^2 + 232x^3 + 351x^4 + 78x^5 + 7x^6)/(1-x)^7. - Emeric Deutsch, Apr 01 2004 a(0)=1, a(1)=1, a(2)=43, a(3)=547, a(4)=3277, a(5)=13021, a(6)=39991, a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7). - Harvey P. Dale, Jul 21 2012 MAPLE A060888 := proc(n)         numtheory[cyclotomic](14, n) ; end proc: seq(A060888(n), n=0..20) ; # R. J. Mathar, Feb 11 2014 MATHEMATICA Table[1-n+n^2-n^3+n^4-n^5+n^6, {n, 0, 30}] (* or *) LinearRecurrence[ {7, -21, 35, -35, 21, -7, 1}, {1, 1, 43, 547, 3277, 13021, 39991}, 30] (* or *) Cyclotomic[14, Range[0, 30]] (* Harvey P. Dale, Jul 21 2012 *) PROG (PARI) { for (n=0, 1000, write("b060888.txt", n, " ", n^6 - n^5 + n^4 - n^3 + n^2 - n + 1); ) } \\ Harry J. Smith, Jul 14 2009 CROSSREFS Sequence in context: A008388 A241939 A251896 * A245427 A229689 A146979 Adjacent sequences:  A060885 A060886 A060887 * A060889 A060890 A060891 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, May 05 2001 STATUS approved

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