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A130483
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Sum {0<=k<=n, k mod 5} (Partial sums of A010874).
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25
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0, 1, 3, 6, 10, 10, 11, 13, 16, 20, 20, 21, 23, 26, 30, 30, 31, 33, 36, 40, 40, 41, 43, 46, 50, 50, 51, 53, 56, 60, 60, 61, 63, 66, 70, 70, 71, 73, 76, 80, 80, 81, 83, 86, 90, 90, 91, 93, 96, 100, 100, 101, 103, 106, 110, 110, 111, 113, 116, 120, 120, 121, 123, 126, 130, 130
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Let A be the Hessenberg n by n matrix defined by: A[1,j]=j mod 5, A[i,i]:=1, A[i,i-1]=-1.Then, for n>=1, a(n)=det(A). [From Milan R. Janjic (agnus(AT)blic.net), Jan 24 2010]
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (1,0,0,0,1,-1).
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FORMULA
| a(n)=10*floor(n/5)+A010874(n)*(A010874(n)+1)/2. G.f.: g(x)=(4x^4+3x^3+2x^2+x)/((1-x^5)(1-x)).
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MAPLE
| a:=n->add(chrem( [n, j], [1, 5] ), j=1..n):seq(a(n), n=0..65); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 07 2009]
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MATHEMATICA
| f[n_]:=Mod[n, 5]; s=0; lst={}; Do[AppendTo[lst, s+=f[n]], {n, 0, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Feb 07 2010]
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CROSSREFS
| Cf. A010872, A010873, A010875, A010876, A010877, A130481, A130482, A130484, A130485.
Sequence in context: A198467 A198456 A032570 * A115012 A200723 A135738
Adjacent sequences: A130480 A130481 A130482 * A130484 A130485 A130486
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KEYWORD
| nonn,easy
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AUTHOR
| Hieronymus Fischer (Hieronymus.Fischer(AT)gmx.de), May 29 2007
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