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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A227100 Number of nX3 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X4 binary array having a sum of two, with rows and columns of the latter in lexicographically nondecreasing order 1
 7, 48, 239, 1084, 4444, 16366, 54500, 166271, 470106, 1243205, 3098315, 7323392, 16507967, 35657274, 74111642, 148760250, 289286122, 546530516, 1005554661, 1805649489, 3170455197, 5452571146, 9198647584, 15243057393, 24840973642 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Column 3 of A227103 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = (1/1307674368000)*n^15 + (1/10897286400)*n^14 + (73/18681062400)*n^13 + (47/479001600)*n^12 + (713/326592000)*n^11 + (407/14515200)*n^10 + (170281/914457600)*n^9 + (790477/304819200)*n^8 + (1304149/186624000)*n^7 + (894611/43545600)*n^6 + (392782843/718502400)*n^5 + (120032611/39916800)*n^4 - (26912769857/756756000)*n^3 + (7313782601/50450400)*n^2 - (8615569/32760)*n + 352 for n>5 EXAMPLE Some solutions for n=4 ..0..1..0....0..0..0....0..1..1....1..0..0....0..1..0....0..0..0....0..0..0 ..1..0..0....1..1..1....1..0..0....1..0..0....1..0..0....0..0..1....0..1..1 ..0..0..1....0..0..0....0..1..1....1..1..1....1..0..0....1..1..1....1..1..0 ..0..0..1....0..1..0....0..1..0....0..1..1....0..1..0....0..1..1....1..0..0 CROSSREFS Sequence in context: A292067 A088143 A124880 * A240334 A171312 A186161 Adjacent sequences: A227097 A227098 A227099 * A227101 A227102 A227103 KEYWORD nonn AUTHOR R. H. Hardin Jul 01 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified January 31 15:11 EST 2023. Contains 359976 sequences. (Running on oeis4.)