cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A280554 T(n,k)=Number of nXk 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.

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%I A280554 #4 Jan 05 2017 08:27:57
%S A280554 0,0,0,0,0,0,1,9,9,1,2,34,50,34,2,6,87,144,144,87,6,13,194,325,382,
%T A280554 325,194,13,29,400,670,832,832,670,400,29,60,790,1316,1666,1764,1666,
%U A280554 1316,790,60,122,1511,2502,3182,3438,3438,3182,2502,1511,122,241,2830,4654
%N A280554 T(n,k)=Number of nXk 0..1 arrays with no element equal to more than one of its horizontal and vertical neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards.
%C A280554 Table starts
%C A280554 ...0....0....0.....1.....2.....6....13.....29.....60....122....241....468
%C A280554 ...0....0....9....34....87...194...400....790...1511...2830...5213...9484
%C A280554 ...0....9...50...144...325...670..1316...2502...4654...8521..15412..27612
%C A280554 ...1...34..144...382...832..1666..3182...5886..10680..19122..33920..59754
%C A280554 ...2...87..325...832..1764..3438..6386..11506..20389..35757..62317.108150
%C A280554 ...6..194..670..1666..3438..6502.11697..20440..35226..60300.102974.175746
%C A280554 ..13..400.1316..3182..6386.11697.20334..34360..57389..95548.159360.266756
%C A280554 ..29..790.2502..5886.11506.20440.34360..56102..90614.146264.237392.388378
%C A280554 ..60.1511.4654.10680.20389.35226.57389..90614.141398.220709.347310.553046
%C A280554 .122.2830.8521.19122.35757.60300.95548.146264.220709.332810.506359.781682
%H A280554 R. H. Hardin, <a href="/A280554/b280554.txt">Table of n, a(n) for n = 1..391</a>
%F A280554 Empirical for column k:
%F A280554 k=1: a(n) = 3*a(n-1) -5*a(n-3) +3*a(n-5) +a(n-6)
%F A280554 k=2: a(n) = 5*a(n-1) -7*a(n-2) -2*a(n-3) +10*a(n-4) -2*a(n-5) -5*a(n-6) +a(n-7) +a(n-8) for n>9
%F A280554 k=3: a(n) = 5*a(n-1) -7*a(n-2) -2*a(n-3) +10*a(n-4) -2*a(n-5) -5*a(n-6) +a(n-7) +a(n-8) for n>10
%F A280554 k=4: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>11
%F A280554 k=5: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>12
%F A280554 k=6: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>12
%F A280554 k=7: a(n) = 6*a(n-1) -12*a(n-2) +5*a(n-3) +12*a(n-4) -12*a(n-5) -3*a(n-6) +6*a(n-7) -a(n-9) for n>12
%e A280554 Some solutions for n=4 k=4
%e A280554 ..0..1..0..1. .0..1..0..0. .0..1..1..0. .0..1..0..1. .0..1..0..1
%e A280554 ..1..0..1..0. .0..1..0..1. .1..1..0..1. .0..1..0..1. .1..0..1..1
%e A280554 ..0..1..1..0. .1..0..1..0. .0..0..1..0. .1..0..1..0. .0..1..0..0
%e A280554 ..1..0..1..0. .0..0..1..0. .1..1..0..1. .1..1..0..0. .0..1..0..1
%Y A280554 Column 1 is A055243(n-4).
%Y A280554 Column 2 is A279128.
%K A280554 nonn,tabl
%O A280554 1,8
%A A280554 _R. H. Hardin_, Jan 05 2017