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 A130487 Sum {0<=k<=n, k mod 9} (Partial sums of A010878). 10
 0, 1, 3, 6, 10, 15, 21, 28, 36, 36, 37, 39, 42, 46, 51, 57, 64, 72, 72, 73, 75, 78, 82, 87, 93, 100, 108, 108, 109, 111, 114, 118, 123, 129, 136, 144, 144, 145, 147, 150, 154, 159, 165, 172, 180, 180, 181, 183, 186, 190, 195, 201, 208, 216, 216, 217, 219, 222, 226 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Let A be the Hessenberg n by n matrix defined by: A[1,j]=j mod 9, A[i,i]:=1, A[i,i-1]=-1.Then, for n>=1, a(n)=det(A). [From Milan Janjic, Jan 24 2010] LINKS FORMULA a(n)=36*floor(n/9)+A010878(n)*(A010878(n)+1)/2. G.f.: g(x)=(sum{1<=k<9, k*x^k})/((1-x^9)(1-x)). Also: g(x)=x(8x^9-9x^8+1)/((1-x^9)(1-x)^3). MAPLE a:=n->add(chrem( [n, j], [1, 9] ), j=1..n):seq(a(n), n=0..58); # [From Zerinvary Lajos, Apr 07 2009] CROSSREFS Cf. A010872, A010873, A010874, A010875, A010876, A010877. A130481, A130482, A130483, A130484, A130485, A130486. Sequence in context: A124157 A033440 A067525 * A231684 A108923 A033441 Adjacent sequences:  A130484 A130485 A130486 * A130488 A130489 A130490 KEYWORD nonn AUTHOR Hieronymus Fischer, May 31 2007 STATUS approved

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Last modified February 21 21:41 EST 2018. Contains 299427 sequences. (Running on oeis4.)