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A130484 a(n) = Sum_{k=0..n} (k mod 6) (Partial sums of A010875). 22
0, 1, 3, 6, 10, 15, 15, 16, 18, 21, 25, 30, 30, 31, 33, 36, 40, 45, 45, 46, 48, 51, 55, 60, 60, 61, 63, 66, 70, 75, 75, 76, 78, 81, 85, 90, 90, 91, 93, 96, 100, 105, 105, 106, 108, 111, 115, 120, 120, 121, 123, 126, 130, 135, 135, 136, 138, 141, 145, 150, 150, 151, 153 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Let A be the Hessenberg n X n matrix defined by A[1,j] = j mod 6, A[i,i]=1, A[i,i-1]=-1. Then, for n >= 1, a(n)=det(A). - Milan Janjic, Jan 24 2010

LINKS

Shawn A. Broyles, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 1, -1).

FORMULA

a(n) = 15*floor(n/6) + A010875(n)*(A010875(n) + 1)/2.

G.f.: (Sum_{k=1..5} k*x^k)/((1-x^6)(1-x)) = x(5x^6 - 6x^5 + 1)/((1-x^6)(1-x)^3).

MATHEMATICA

Accumulate[Mod[Range[0, 70], 6]] (* or *) Accumulate[PadRight[ {}, 70, Range[0, 5]]] (* Harvey P. Dale, Jul 12 2016 *)

PROG

(PARI) a(n) = sum(k=0, n, k % 6); \\ Michel Marcus, Apr 28 2018

CROSSREFS

Cf. A010872, A010873, A010874, A010876, A010877, A130481, A130482, A130483, A130485.

Sequence in context: A105333 A126234 A259604 * A074374 A109804 A231672

Adjacent sequences:  A130481 A130482 A130483 * A130485 A130486 A130487

KEYWORD

nonn

AUTHOR

Hieronymus Fischer, May 31 2007

STATUS

approved

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Last modified November 19 00:12 EST 2018. Contains 317332 sequences. (Running on oeis4.)