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

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A201841 Number of zero-sum nX2 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor 1
 1, 5, 25, 97, 411, 1897, 8741, 41689, 201985, 987407, 4891069, 24457873, 123131033, 623695509, 3174983801, 16227954653, 83226630287, 428047598133, 2206766393985, 11399915802567, 58993096946055, 305739808201773, 1586610751415691 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 2 of A201847 LINKS R. H. Hardin, Table of n, a(n) for n = 1..95 EXAMPLE Some solutions for n=8 .-1.-1...-1..0....1.-1....1..1....1..1...-1..0...-1.-1...-1.-1...-1.-1...-1..0 ..1..1...-1..0....1.-1....1.-1....1..0...-1..0....0.-1....1..1...-1.-1...-1..0 ..0..1....1..1....1..0....1.-1...-1..0....0..1....0..1....0..1....0..1....0..0 ..0..1...-1.-1...-1..0...-1.-1...-1..1....0..1....0..1....0..1....0..1....0..0 .-1..1....1.-1...-1..0....1..1...-1..1....0..0....1..1....0..0....0..0...-1..1 .-1..1....1..1....1..0....0..0....0..0...-1.-1...-1..1....0.-1...-1..1...-1..1 ..0.-1....1.-1....1.-1...-1.-1....0..0....0..1...-1..0....0.-1...-1..1....0..0 ..0.-1....1.-1....1.-1....0..0...-1.-1....0..1....0..0....0..0....1..1....1..1 CROSSREFS Sequence in context: A223945 A197085 A273747 * A146830 A316778 A255612 Adjacent sequences:  A201838 A201839 A201840 * A201842 A201843 A201844 KEYWORD nonn AUTHOR R. H. Hardin Dec 06 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.

Last modified December 1 11:07 EST 2021. Contains 349429 sequences. (Running on oeis4.)