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A220795 Equals two maps: number of 2Xn binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal, diagonal and antidiagonal neighbors in a random 0..2 2Xn array 2
1, 6, 19, 76, 267, 1074, 4069, 15916, 62161, 243418, 954189, 3745072, 14698115, 57707746, 226582983, 889710492, 3493659533, 13718948094, 53871964175, 211547211964, 830715606031, 3262105325370, 12809842147609, 50302517147348 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 2 of A220794

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) +10*a(n-2) -34*a(n-3) -66*a(n-4) +98*a(n-5) +320*a(n-6) -66*a(n-7) -916*a(n-8) -306*a(n-9) +1454*a(n-10) +1054*a(n-11) -1038*a(n-12) -1690*a(n-13) -376*a(n-14) +1514*a(n-15) +1301*a(n-16) -1114*a(n-17) -1008*a(n-18) +796*a(n-19) -568*a(n-20) -624*a(n-21) +720*a(n-22) -144*a(n-23) +64*a(n-24) +64*a(n-25)

EXAMPLE

Some solutions for n=3

..1..0..0....0..1..1....1..0..1....0..1..0....0..0..1....1..0..1....0..1..1

..0..0..0....0..1..1....1..0..1....0..0..0....1..0..1....1..0..0....1..1..0

CROSSREFS

Sequence in context: A123950 A100191 A191585 * A026545 A041937 A279512

Adjacent sequences:  A220792 A220793 A220794 * A220796 A220797 A220798

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 21 2012

STATUS

approved

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Last modified March 26 07:22 EDT 2017. Contains 284111 sequences.