The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A108356 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A108356

Count, repeating multiples of 3 four times, all other numbers twice.
(history; published version)

#21 by Michael De Vlieger at Sat Sep 09 06:52:55 EDT 2023

STATUS

reviewed

approved

#20 by Stefano Spezia at Sat Sep 09 02:18:13 EDT 2023

STATUS

proposed

reviewed

#19 by Jon E. Schoenfield at Fri Sep 08 20:43:14 EDT 2023

STATUS

editing

proposed

#18 by Jon E. Schoenfield at Fri Sep 08 20:42:57 EDT 2023

FORMULA

a(n) = Sum_{k=0..floor(n/2)} (Sum_{j=0..n-2k2*k} ((C(k, j)*C(n-k-j, k)*floor((j+2)/2)) mod 2).

Discussion

Fri Sep 08

20:43

Jon E. Schoenfield: I think this is right.

#17 by Jon E. Schoenfield at Fri Sep 08 20:33:00 EDT 2023

FORMULA

a(n) = a(n-1) + a(n-8) - a(n-9).

a(n) = sumSum_{k=0..floor(n/2), mod} (sumSum_{j=0..n-2k, } C(k, j)*C(n-k-j, k)*floor((j+2)/2)}, ) mod 2)}.

STATUS

proposed

editing

Discussion

Fri Sep 08

20:33

Jon E. Schoenfield: I tried to correct the summation format (and fix the "mod" format problem)....

#16 by Michel Marcus at Fri Sep 08 08:58:04 EDT 2023

STATUS

editing

proposed

#15 by Michel Marcus at Fri Sep 08 08:58:02 EDT 2023

FORMULA

G.f.: (1+x^2+x^4)/(1-x-x^8+x^9).

a(n) = a(n-1)+a(n-8)-a(n-9).

G.f.: (1+x^2+x^4)/(1-x-x^8+x^9); a(n)=a(n-1)+a(n-8)-a(n-9); a(n) = sum{k=0..floor(n/2), mod(sum{j=0..n-2k, C(k, j)C(n-k-j, k)floor((j+2)/2)}, 2)}.

STATUS

proposed

editing

#14 by Ridouane Oudra at Fri Sep 08 07:53:25 EDT 2023

STATUS

editing

proposed

#13 by Ridouane Oudra at Fri Sep 08 07:51:51 EDT 2023

FORMULA

a(n) = floor(n/2) - floor((n+2)/8) + 1. - Ridouane Oudra, Sep 08 2023

MAPLE

seq(floor(n/2) - floor((n+2)/8) + 1, n=0..60); # Ridouane Oudra, Sep 08 2023

STATUS

approved

editing

#12 by Harvey P. Dale at Fri Oct 06 13:56:22 EDT 2017

STATUS

editing

approved