A224659 -id:A224659 - cp's OEIS frontend

A224676 T(n,k)=Number of (n+1)X(k+1) 0..2 matrices with each 2X2 subblock idempotent.

12, 25, 25, 41, 50, 41, 70, 76, 76, 70, 115, 123, 108, 123, 115, 189, 191, 170, 170, 191, 189, 308, 300, 257, 260, 257, 300, 308, 501, 470, 398, 381, 381, 398, 470, 501, 813, 741, 617, 573, 542, 573, 617, 741, 813, 1318, 1173, 967, 864, 793, 793, 864, 967, 1173, 1318

Offset: 1

R. H. Hardin Apr 14 2013

Table starts
...12...25...41...70..115..189..308..501...813..1318..2135..3457..5596..9057
...25...50...76..123..191..300..470..741..1173..1866..2980..4775..7671.12348
...41...76..108..170..257..398..617..967..1525..2421..3862..6185..9934.15990
...70..123..170..260..381..573..864.1322..2043..3191..5026..7972.12713.20357
..115..191..257..381..542..793.1166.1746..2650..4080..6355..9996.15843.25257
..189..300..398..573..793.1126.1608.2343..3471..5236..8022.12457.19553.30950
..308..470..617..864.1166.1608.2230.3157..4554..6711.10083.15415.23907.37504
..501..741..967.1322.1746.2343.3157.4336..6072..8705.12767.19130.29198.45247
..813.1173.1525.2043.2650.3471.4554.6072..8246.11470.16359.23922.35783.54575
.1318.1866.2421.3191.4080.5236.6711.8705.11470.15458.21373.30371.44312.66212

			Some solutions for n=3 k=4
..1..1..1..1..0....1..0..1..0..2....1..0..1..0..0....0..1..0..0..2
..0..0..0..0..0....1..0..1..0..1....1..0..1..0..1....0..1..0..0..1
..0..0..0..0..0....1..0..1..0..1....1..0..1..0..1....0..1..0..0..1
..0..0..1..1..1....0..0..1..0..1....1..0..1..0..1....0..1..0..0..1

R. H. Hardin, Table of n, a(n) for n = 1..967

Diagonal is A224659(n+1)

Empirical for column k:
k=1: a(n) = 2*a(n-1) -a(n-3)
k=2: a(n) = 4*a(n-1) -5*a(n-2) +a(n-3) +2*a(n-4) -a(n-5)
k=3..7+: a(n) = 4*a(n-1) -5*a(n-2) +a(n-3) +2*a(n-4) -a(n-5) for n>6

cp's OEIS Frontend

A224676 T(n,k)=Number of (n+1)X(k+1) 0..2 matrices with each 2X2 subblock idempotent.

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