VOOZH about

URL: https://oeis.org/A166091

⇱ A166091 - OEIS

login
A166091
Square array A(row>=0, col>=0) = (A166092(row,col)-3)/4, listed antidiagonally as A(0,0), A(0,1), A(1,0), A(0,2), A(1,1), A(2,0), ...
7
0, 1, 2, 3, 79, 4, 5, 151, 8, 103, 7, 175, 14, 409, 22, 9, 223, 15, 589, 43, 10, 11, 265, 25, 998, 143, 31, 12, 13, 275, 32, 1297, 157, 73, 20, 16, 17, 283, 62, 1364, 182, 158, 55, 28, 6, 19, 361, 69, 1891, 293, 164, 183, 34, 26, 52, 21, 373, 74, 1952, 397, 401
OFFSET
0,3
COMMENTS
Note: This is not a permutation of nonnegative integers, as for some odd n, A166040(n) gets even value, the first example being A166040(49)=32, thus 24 (= (49-1)/2) is missing from here, and correspondingly, 99 (= 2*49 + 1) is missing from A166092. Sequence A165602 gives the natural numbers missing from this table.
LINKS
EXAMPLE
The top left corner of the array:
0, 1, 3, 5, 7, 9, ...
2, 79, 151, 175, 223, 265, ...
4, 8, 14, 15, 25, 32, ...
103, 409, 589, 998, 1297, 1364, ...
22, 43, 143, 157, 182, 293, ...
PROG
(Scheme)
(define (A166091 n) (A166091bi (A025581 n) (A002262 n)))
(define (A166091bi n k) (let ((m (A005408 k))) (let loop ((i 0) (n n)) (cond ((= m (A166086 i)) (if (zero? n) i (loop (1+ i) (-1+ n)))) (else (loop (1+ i) n))))))
CROSSREFS
See A166092. The leftmost column: A166094. The first five rows: A165468, A166052, A166054, A166056, A166058. Cf. also A112060.
Sequence in context: A377690 A306195 A091825 * A371141 A370993 A371228
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Oct 08 2009
STATUS
approved