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A220325 Equals two maps: number of nX4 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..1 nX4 array 1
4, 48, 572, 6657, 76627, 876714, 10004541, 114058230, 1299991681, 14816159113, 168863397427, 1924606619479, 21935746576784, 250014218249170, 2849559239020408, 32478119824983512, 370172462886188547 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 4 of A220328

LINKS

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

FORMULA

Empirical: a(n) = 52*a(n-1) -1250*a(n-2) +18642*a(n-3) -194453*a(n-4) +1512860*a(n-5) -9129049*a(n-6) +43823835*a(n-7) -170215806*a(n-8) +540993502*a(n-9) -1417406111*a(n-10) +3076408923*a(n-11) -5554889698*a(n-12) +8398935833*a(n-13) -10787536090*a(n-14) +12135358811*a(n-15) -12598845224*a(n-16) +12820387027*a(n-17) -13258166832*a(n-18) +14036219536*a(n-19) -15126263888*a(n-20) +15968958579*a(n-21) -15322438978*a(n-22) +12752922922*a(n-23) -9963260043*a(n-24) +8938384993*a(n-25) -9062026289*a(n-26) +8132182176*a(n-27) -5833978765*a(n-28) +3839464387*a(n-29) -2914935368*a(n-30) +2269830690*a(n-31) -1376357333*a(n-32) +584276484*a(n-33) -210575330*a(n-34) +122997352*a(n-35) -93676127*a(n-36) +53337463*a(n-37) -20323630*a(n-38) +4959164*a(n-39) -1342573*a(n-40) +1282335*a(n-41) -871329*a(n-42) +302448*a(n-43) -65056*a(n-44) +9552*a(n-45) -576*a(n-46) for n>47

EXAMPLE

Some solutions for n=3

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

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

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

CROSSREFS

Sequence in context: A159903 A099671 A196963 * A265419 A226705 A126967

Adjacent sequences:  A220322 A220323 A220324 * A220326 A220327 A220328

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 10 2012

STATUS

approved

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Last modified June 23 02:27 EDT 2021. Contains 345395 sequences. (Running on oeis4.)