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A361976
(2,2)-block array, B(2,2), of the natural number array (A000027), read by descending antidiagonals.
4
11, 31, 39, 67, 75, 83, 119, 127, 135, 143, 187, 195, 203, 211, 219, 271, 279, 287, 295, 303, 311, 371, 379, 387, 395, 403, 411, 419, 487, 495, 503, 511, 519, 527, 535, 543, 619, 627, 635, 643, 651, 659, 667, 675, 683, 767, 775, 783, 791, 799, 807, 815, 823
OFFSET
1,1
COMMENTS
We begin with a definition. Suppose that W = (w(i,j)), where i >= 1 and j >= 1, is an array of numbers such that if m and n satisfy 1 <= m < n, then there exists k such that w(m,k+h) < w(n,h+1) < w(m,k+h+1) for every h >= 0 . Then W is a row-splitting array. The array B(2,2) is a row-splitting array. The rows and columns of B(2,2) are linearly recurrent with signature (3,-3,1). It appears that the order array (as defined in A333029) of B(2,2) is given by A000027.
FORMULA
B(2,2) = (b(i,j)), where b(i,j) = w(2i-1,2j-1) + w(2i-1,2j) + w(2i,2j-1) + w(2i, 2j) for i >= 1, j >=1, where (w(i,j)) is the natural number array (A000027).
b(i,j) = 8(i+j)^2 - 12i - 20 j + 11.
EXAMPLE
Corner of B(2,2):
11 31 67 119 187 271
39 75 127 195 279 379
83 135 203 287 387 503
143 211 295 395 511 643
219 303 403 519 651 799
MATHEMATICA
zz = 10; z = 13;
w[n_, k_] := n + (n + k - 2) (n + k - 1)/2;
t[n_, k_] := w[2 n - 1, 2 k - 1] + w[2 n - 1, 2 k] + w[2 n, 2 k - 1] + w[2 n, 2 k]
Table[t[n - k + 1, k], {n, 12}, {k, n, 1, -1}] // Flatten (*A361976 sequence*)
TableForm[Table[t[h, k], {h, 1, zz}, {k, 1, z}]] (*A361976 array*)
CROSSREFS
Cf. A000027, A333029, A361974 (array B(1,2)), A361975 (array B(2,1)).
Sequence in context: A022423 A173972 A167488 * A298566 A090756 A038351
KEYWORD
nonn,tabl
AUTHOR
Clark Kimberling, Apr 01 2023
STATUS
approved