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 A256997 Square array A(row,col) read by antidiagonals: A(1,col) = A055938(col), and for row > 1, A(row,col) = A005187(A(row-1,col)). 13
 2, 5, 3, 6, 8, 4, 9, 10, 15, 7, 12, 16, 18, 26, 11, 13, 22, 31, 34, 49, 19, 14, 23, 41, 57, 66, 95, 35, 17, 25, 42, 79, 110, 130, 184, 67, 20, 32, 47, 81, 153, 215, 258, 364, 131, 21, 38, 63, 89, 159, 302, 424, 514, 723, 259, 24, 39, 73, 120, 174, 312, 599, 844, 1026, 1440, 515, 27, 46, 74, 143, 236, 343, 620, 1192, 1683, 2050, 2876, 1027 (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 A256995. If we assume that a(1) = 1 (but which is not explicitly included here because outside of the array proper), then A256998 gives the inverse permutation. LINKS FORMULA A(1,col) = A055938(col), and for row > 1, A(row,col) = A005187(A(row-1,col)). EXAMPLE The top left corner of the array:     2,    5,    6,    9,   12,   13,   14,   17,   20,   21,    24,    27     3,    8,   10,   16,   22,   23,   25,   32,   38,   39,    46,    50     4,   15,   18,   31,   41,   42,   47,   63,   73,   74,    88,    97     7,   26,   34,   57,   79,   81,   89,  120,  143,  145,   173,   191    11,   49,   66,  110,  153,  159,  174,  236,  281,  287,   341,   375    19,   95,  130,  215,  302,  312,  343,  467,  558,  568,   677,   743    35,  184,  258,  424,  599,  620,  680,  928, 1111, 1132,  1349,  1479    67,  364,  514,  844, 1192, 1235, 1356, 1852, 2216, 2259,  2693,  2951   131,  723, 1026, 1683, 2380, 2464, 2707, 3697, 4428, 4512,  5381,  5895   259, 1440, 2050, 3360, 4755, 4924, 5408, 7387, 8851, 9020, 10757, 11783   ... PROG (Scheme) (define (A256997 n) (if (<= n 1) n (A256997bi (A002260 (- n 1)) (A004736 (- n 1))))) (define (A256997bi row col) (if (= 1 row) (A055938 col) (A005187 (A256997bi (- row 1) col)))) CROSSREFS Cf. A005187, A055938 (row 1), A256994 (column 1), A256989 (row index), A256990 (column index). Inverse: A256998. Transpose: A256995. Cf. also A254107, A255557 (variants), A246278 (another thematically similar construction). Sequence in context: A024871 A222072 A246007 * A335499 A239970 A111202 Adjacent sequences:  A256994 A256995 A256996 * A256998 A256999 A257000 KEYWORD nonn,tabl AUTHOR Antti Karttunen, Apr 14 2015 STATUS approved

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Last modified September 30 23:44 EDT 2020. Contains 337440 sequences. (Running on oeis4.)