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A257258
Square array A(row,col) = (1/2) * (A255127(row,col+1) - A255127(row,col)): half of the first differences of each row of Ludic array.
4
1, 1, 3, 1, 3, 7, 1, 3, 8, 12, 1, 3, 7, 14, 22, 1, 3, 8, 13, 24, 30, 1, 3, 7, 14, 24, 30, 42, 1, 3, 8, 12, 26, 32, 43, 61, 1, 3, 7, 13, 24, 33, 47, 63, 71, 1, 3, 8, 14, 24, 31, 43, 66, 72, 88, 1, 3, 7, 13, 22, 30, 47, 60, 73, 83, 108, 1, 3, 8, 12, 24, 32, 43, 66, 71, 90, 117, 126
OFFSET
1,3
COMMENTS
The array A(row,col) is read by downwards antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), ...
FORMULA
A(row,col) = (1/2) * (A255127(row,col+1) - A255127(row,col)).
A(row,col) = A257257(row,col)/2.
EXAMPLE
The top left corner of the array:
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3
7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8
12, 14, 13, 14, 12, 13, 14, 13, 12, 14, 13, 14, 12, 13, 14, 13
22, 24, 24, 26, 24, 24, 22, 24, 26, 24, 24, 24, 22, 26, 24, 24
30, 30, 32, 33, 31, 30, 32, 31, 30, 35, 30, 30, 31, 32, 30, 33
42, 43, 47, 43, 47, 43, 41, 46, 44, 46, 44, 45, 45, 42, 45, 45
61, 63, 66, 60, 66, 63, 65, 63, 60, 66, 64, 63, 65, 64, 63, 65
71, 72, 73, 71, 73, 69, 75, 74, 70, 74, 73, 69, 75, 69, 75, 74
88, 83, 90, 84, 88, 89, 85, 89, 85, 90, 87, 86, 88, 89, 88, 87
108, 117, 113, 121, 114, 113, 120, 109, 117, 123, 110, 115, 117, 113, 117, 118
126, 135, 127, 137, 129, 127, 129, 138, 131, 133, 129, 128, 132, 138, 132, 132
137, 142, 134, 142, 152, 135, 141, 139, 147, 141, 141, 138, 141, 144, 146, 138
154, 158, 157, 158, 160, 158, 156, 154, 162, 168, 158, 151, 158, 157, 161, 157
180, 180, 177, 184, 180, 186, 185, 184, 176, 180, 190, 177, 185, 190, 176, 184
206, 217, 212, 210, 213, 220, 213, 210, 216, 212, 211, 222, 212, 211, 215, 213
...
PROG
(Scheme)
(define (A257258 n) (A257258bi (A002260 n) (A004736 n)))
(define (A257258bi row col) (* (/ 1 2) (- (A255127bi row (+ 1 col)) (A255127bi row col)))) ;; Code for A255127bi given in A255127.
CROSSREFS
Column 1: A256483.
Cf. A255127, A257257 (same array but with terms multiplied by 2).
Sequence in context: A152903 A226522 A122507 * A259325 A094250 A208517
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Apr 29 2015
STATUS
approved