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 A210536 T(n,k) = 3*n + (k-1) mod 3 - 2; n , k > 0, read by antidiagonals. 0
 1, 2, 4, 3, 5, 7, 1, 6, 8, 10, 2, 4, 9, 11, 13, 3, 5, 7, 12, 14, 16, 1, 6, 8, 10, 15, 17, 19, 2, 4, 9, 11, 13, 18, 20, 22, 3, 5, 7, 12, 14, 16, 21, 23, 25, 1, 6, 8, 10, 15, 17, 19, 24, 26, 28, 2, 4, 9, 11, 13, 18, 20, 22, 27, 29, 2, 9, 31, 3, 5, 7, 12, 14, 16 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Columns 3*k-2 are A016777, Columns 3*k-1 are A016789, Columns 3*k   are A008585. Rows 1 is A010882. LINKS Boris Putievskiy, Transformations [of] Integer Sequences And Pairing Functions arXiv:1212.2732 [math.CO], 2012. FORMULA a(n) = 3*A002260(n) + (A004736(n) - 1) mod 3 - 2. a(n) = 3*i + (j-1) mod 3 - 2, where i = n-t*(t+1)/2, j = (t*t+3*t+4)/2-n, t=floor((-1+sqrt(8*n-7))/2). EXAMPLE The start of the sequence as table: 1....2...3...1...2...3...1...2...3... 4....5...6...4...5...6...4...5...6... 7....8...9...7...8...9...7...8...9... 10..11..12..10..11..12..10..11..12... 13..14..15..13..14..15..13..14..15... 16..17..18..16..17..18..16..17..18... 19..20..21..19..20..21..19..20..21... 22..23..24..22..23..24..22..23..24... 25..26..27..25..26..27..25..26..27... . . . The start of the sequence as triangle array read by rows: 1; 2,4; 3,5,7; 1,6,8,10; 2,4,9,11,13; 3,5,7,12,14,16; 1,6,8,10,15,17,19; 2,4,9,11,13,18,20,22; 3,5,7,12,14,16,21,23,25; . . . PROG (Python) t=int((math.sqrt(8*n-7) - 1)/ 2) i=n-t*(t+1)/2 j=(t*t+3*t+4)/2-n result=3*i + (j-1) % 3 - 2 CROSSREFS Cf. A016777, A016789, A008585, A010882, A002260, A004736, A131225. Sequence in context: A102568 A338834 A338835 * A102767 A336640 A258238 Adjacent sequences:  A210533 A210534 A210535 * A210537 A210538 A210539 KEYWORD nonn,tabl AUTHOR Boris Putievskiy, Jan 29 2013 STATUS approved

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Last modified January 21 18:08 EST 2022. Contains 350479 sequences. (Running on oeis4.)