login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A202965 Number of arrays of 5 integers in -n..n with sum zero and adjacent elements differing in absolute value. 1
2, 82, 414, 1562, 4048, 9010, 17296, 30648, 50232, 78388, 116614, 167824, 233858, 318234, 423094, 552554, 709104, 897434, 1120360, 1383176, 1689016, 2043772, 2450910, 2916896, 3445538, 4043906, 4716110, 5469818, 6309488, 7243362, 8276224 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A202962.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 2*a(n-1) -a(n-3) -2*a(n-5) +2*a(n-6) +a(n-8) -2*a(n-10) +a(n-11).

Empirical g.f.: 2*x*(1 + 39*x + 125*x^2 + 368*x^3 + 503*x^4 + 666*x^5 + 499*x^6 + 384*x^7 + 120*x^8 + 55*x^9) / ((1 - x)^5*(1 + x)^2*(1 + x^2)*(1 + x + x^2)). - Colin Barker, Jun 03 2018

EXAMPLE

Some solutions for n=5:

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

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

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

..2....0...-2....1....2...-2...-2....2....4....4....0...-1....4....4....3....0

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

CROSSREFS

Cf. A202962.

Sequence in context: A120826 A343588 A259308 * A307583 A061994 A332584

Adjacent sequences:  A202962 A202963 A202964 * A202966 A202967 A202968

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 26 2011

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 January 25 10:03 EST 2022. Contains 350565 sequences. (Running on oeis4.)