login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A247929 Number of length 2+4 0..n arrays with some disjoint pairs in every consecutive five terms having the same sum 1
64, 529, 2760, 9569, 25512, 57769, 117256, 216937, 376656, 613721, 956736, 1432465, 2078080, 2925313, 4025112, 5420273, 7170312, 9325369, 11960584, 15142537, 18952080, 23466953, 28787520, 35002753, 42229648, 50570737, 60151800, 71100353 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A247927

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..152

FORMULA

Empirical: a(n) = a(n-2) +a(n-3) +a(n-4) -a(n-7) -2*a(n-8) -2*a(n-9) -a(n-10) +2*a(n-12) +2*a(n-13) +2*a(n-14) +2*a(n-15) -a(n-17) -2*a(n-18) -2*a(n-19) -a(n-20) +a(n-23) +a(n-24) +a(n-25) -a(n-27)

Also a polynomial of degree 5 plus a linear quasipolynomial with period 420; the first 12 are :

Empirical for n mod 420 = 0: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58568/35)*n^2 - (60384/35)*n + 1

Empirical for n mod 420 = 1: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58358/35)*n^2 - (50934/35)*n + (27463/105)

Empirical for n mod 420 = 2: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58568/35)*n^2 - (57024/35)*n - (29047/105)

Empirical for n mod 420 = 3: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58358/35)*n^2 - (50934/35)*n - (9111/7)

Empirical for n mod 420 = 4: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58568/35)*n^2 - (60384/35)*n - (42551/105)

Empirical for n mod 420 = 5: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58358/35)*n^2 - (47574/35)*n - (5003/3)

Empirical for n mod 420 = 6: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58568/35)*n^2 - (60384/35)*n + (8651/35)

Empirical for n mod 420 = 7: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58358/35)*n^2 - (50934/35)*n - (15311/15)

Empirical for n mod 420 = 8: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58568/35)*n^2 - (57024/35)*n - (14435/21)

Empirical for n mod 420 = 9: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58358/35)*n^2 - (50934/35)*n - (24387/35)

Empirical for n mod 420 = 10: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58568/35)*n^2 - (60384/35)*n + (6365/21)

Empirical for n mod 420 = 11: a(n) = 2*n^5 + 75*n^4 - (1460/3)*n^3 + (58358/35)*n^2 - (47574/35)*n - (261217/105)

EXAMPLE

Some solutions for n=6

..2....2....1....2....4....3....2....3....2....0....1....0....6....4....6....3

..3....3....4....5....4....1....1....6....6....5....5....4....5....5....2....4

..4....6....1....5....5....2....6....4....1....1....0....5....5....1....2....2

..3....1....6....6....3....4....0....4....5....1....4....1....3....0....5....1

..5....5....4....4....4....5....3....1....2....6....1....0....3....4....6....0

..2....2....3....0....3....1....2....3....1....5....0....4....4....5....1....2

CROSSREFS

Sequence in context: A115740 A100415 A200841 * A070054 A265636 A209787

Adjacent sequences:  A247926 A247927 A247928 * A247930 A247931 A247932

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 26 2014

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 12 09:24 EDT 2021. Contains 344946 sequences. (Running on oeis4.)