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A204224 Number of (n+1)X3 0..2 arrays with the sums of 2X2 subblocks nondecreasing rightwards and downwards 1
450, 4539, 44641, 312001, 2173565, 12097076, 67329896, 320850651, 1529688095, 6522838147, 27826525857, 109309929157, 429561634288, 1586242394564, 5859703202568, 20639200392449, 72725001826184, 246982200868842 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A204230

LINKS

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

FORMULA

Empirical: a(n) = 9*a(n-1) +65*a(n-2) -813*a(n-3) -1503*a(n-4) +35067*a(n-5) -2049*a(n-6) -960243*a(n-7) +1086240*a(n-8) +18711228*a(n-9) -35736696*a(n-10) -275381736*a(n-11) +714658500*a(n-12) +3165994812*a(n-13) -10469468628*a(n-14) -28924095228*a(n-15) +120561637986*a(n-16) +210319415742*a(n-17) -1132860637250*a(n-18) -1190202257382*a(n-19) +8890114025950*a(n-20) +4801619959530*a(n-21) -59186272390110*a(n-22) -8367164615610*a(n-23) +338018085156660*a(n-24) -63026938123020*a(n-25) -1669263148180740*a(n-26) +783202925756340*a(n-27) +7168284121132980*a(n-28) -5196566728384740*a(n-29) -26866295989193748*a(n-30) +26010783052803972*a(n-31) +88048679140737015*a(n-32) -106748031772881279*a(n-33) -252329474348288919*a(n-34) +371635847674498251*a(n-35) +630909828966841993*a(n-36) -1116759425621881869*a(n-37) -1368846121844868905*a(n-38) +2925275798772753429*a(n-39) +2549493296941549716*a(n-40) -6718378143067818744*a(n-41) -3990279397586265900*a(n-42) +13573200380588028348*a(n-43) +5003881995007001088*a(n-44) -24158694316978174512*a(n-45) -4356492449072602896*a(n-46) +37885311670133837328*a(n-47) +702180134840233920*a(n-48) -52281979345965347328*a(n-49) +6495657021495425856*a(n-50) +63334702238132746176*a(n-51) -16079014545805946880*a(n-52) -67090134345597242112*a(n-53) +25187434137260649728*a(n-54) +61801025531016991488*a(n-55) -30523610020098282496*a(n-56) -49124893907374282752*a(n-57) +30216827194676075520*a(n-58) +33334146513723036672*a(n-59) -24903026047945359360*a(n-60) -19010417886235054080*a(n-61) +17168181780647301120*a(n-62) +8895860007639920640*a(n-63) -9868786556970516480*a(n-64) -3276824012368773120*a(n-65) +4685347765788917760*a(n-66) +868947223463608320*a(n-67) -1807894348725288960*a(n-68) -120651665681940480*a(n-69) +553134494117265408*a(n-70) -17459153936842752*a(n-71) -129178265777602560*a(n-72) +14777776041099264*a(n-73) +21637807214690304*a(n-74) -4007539482034176*a(n-75) -2315214083063808*a(n-76) +570630428688384*a(n-77) +118881339310080*a(n-78) -35664401793024*a(n-79)

EXAMPLE

Some solutions for n=4

..1..1..2....0..0..2....2..1..1....0..1..2....1..2..2....0..1..2....1..2..1

..1..0..1....1..2..0....1..1..2....2..1..2....1..2..0....2..1..0....0..2..2

..1..2..2....1..2..2....1..2..2....2..1..2....1..2..2....0..1..2....1..2..1

..2..1..1....2..2..1....2..1..2....1..2..1....1..2..0....1..2..0....0..2..2

..1..2..2....1..2..2....2..2..2....1..2..2....1..2..2....0..2..1....1..2..2

CROSSREFS

Sequence in context: A253369 A253376 A253150 * A235438 A204719 A235403

Adjacent sequences:  A204221 A204222 A204223 * A204225 A204226 A204227

KEYWORD

nonn

AUTHOR

R. H. Hardin Jan 13 2012

STATUS

approved

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Last modified September 28 16:23 EDT 2021. Contains 347716 sequences. (Running on oeis4.)