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A256995 Square array A(row,col) read by antidiagonals: A(row,1) = A055938(row), and for col > 1, A(row,col) = A005187(A(row,col-1)). 8
2, 3, 5, 4, 8, 6, 7, 15, 10, 9, 11, 26, 18, 16, 12, 19, 49, 34, 31, 22, 13, 35, 95, 66, 57, 41, 23, 14, 67, 184, 130, 110, 79, 42, 25, 17, 131, 364, 258, 215, 153, 81, 47, 32, 20, 259, 723, 514, 424, 302, 159, 89, 63, 38, 21, 515, 1440, 1026, 844, 599, 312, 174, 120, 73, 39, 24, 1027, 2876, 2050, 1683, 1192, 620, 343, 236, 143, 74, 46, 27 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
2,1
COMMENTS
The array is read by antidiagonals: A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), etc.
This is transpose of array A256997.
If we assume that a(1) = 1 (but which is not explicitly included here because outside of the array proper), then A256996 gives the inverse permutation.
LINKS
FORMULA
A(row,1) = A055938(row), and for col > 1, A(row,col) = A005187(A(row,col-1)).
EXAMPLE
The top left corner of the array:
2, 3, 4, 7, 11, 19, 35, 67, 131, 259, 515, 1027
5, 8, 15, 26, 49, 95, 184, 364, 723, 1440, 2876, 5745
6, 10, 18, 34, 66, 130, 258, 514, 1026, 2050, 4098, 8194
9, 16, 31, 57, 110, 215, 424, 844, 1683, 3360, 6716, 13425
12, 22, 41, 79, 153, 302, 599, 1192, 2380, 4755, 9504, 19004
13, 23, 42, 81, 159, 312, 620, 1235, 2464, 4924, 9841, 19675
14, 25, 47, 89, 174, 343, 680, 1356, 2707, 5408, 10812, 21617
17, 32, 63, 120, 236, 467, 928, 1852, 3697, 7387, 14765, 29521
20, 38, 73, 143, 281, 558, 1111, 2216, 4428, 8851, 17696, 35388
21, 39, 74, 145, 287, 568, 1132, 2259, 4512, 9020, 18033, 36059
...
PROG
(Scheme)
(define (A256995 n) (if (<= n 1) n (A256995bi (A002260 (- n 1)) (A004736 (- n 1)))))
(define (A256995bi row col) (if (= 1 col) (A055938 row) (A005187 (A256995bi row (- col 1)))))
CROSSREFS
Inverse permutation: A256996.
Transpose: A256997.
Cf. A005187, A055938 (column 1), A256994 (row 1), A256989 (column index), A256990 (row index).
Cf. also A254105, A255555 (variants), A114537, A246279 (other thematically similar constructions).
Sequence in context: A347423 A255234 A364225 * A249129 A065561 A245708
KEYWORD
nonn,tabl
AUTHOR
Antti Karttunen, Apr 14 2015
STATUS
approved

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Last modified March 28 16:12 EDT 2024. Contains 371254 sequences. (Running on oeis4.)