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 A064790 Inverse permutation to A060734. 4
 1, 3, 5, 2, 6, 9, 13, 8, 4, 10, 14, 19, 25, 18, 12, 7, 15, 20, 26, 33, 41, 32, 24, 17, 11, 21, 27, 34, 42, 51, 61, 50, 40, 31, 23, 16, 28, 35, 43, 52, 62, 73, 85, 72, 60, 49, 39, 30, 22, 36, 44, 53, 63, 74, 86, 99, 113, 98, 84, 71, 59, 48, 38, 29, 45, 54, 64, 75, 87, 100, 114 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS From Boris Putievskiy, Mar 14 2013: (Start) a(n) is a pairing function: a function that reversibly maps Z^{+} x Z^{+} onto Z^{+}, where Z^{+} is the set of integer positive numbers. Layer is pair of sides of square from T(1,n) to T(n,n) and  from T(n,n) to T(n,1). This sequence is A188568 as table read  by boustrophedonic ("ox-plowing") method - layer clockwise, layer counterclockwise and so. The same table A188568 read layer by layer clockwise is A194280. (End) LINKS Boris Putievskiy, Transformations Integer Sequences And Pairing Functions arXiv:1212.2732 [math.CO] Eric Weisstein's MathWorld, Pairing Function FORMULA a(n) = (i+j-1)*(i+j-2)/2+i, where i=min(t; t^2-n+1), j=min(t; n-(t-1)^2), t=floor(sqrt(n-1))+1. - Boris Putievskiy, Dec 24 2012 EXAMPLE From Boris Putievskiy, Mar 14 2013: (Start) The start of the sequence as table: 1....2...6...7..15..16..28... 3....5...9..12..20..23..35... 4....8..13..18..26..31..43... 10..14..19..25..33..40..52... 11..17..24..32..41..50..62... 21..27..34..42..51..61..73... 22..30..39..49..60..72..85... . . . The start of the sequence as triangular array read by rows: 1; 3,5,2; 6,9,13,8,4; 10,14,19,25,18,12,7; 15,20,26,33,41,32,24,17,11; 21,27,34,42,51,61,50,40,31,23,16; 28,35,43,52,62,73,85,72,60,49,39,30,22; . . . Row number r contains 2*r-1 numbers. (End) CROSSREFS Cf. A060734, A064788, A188568, A194280. Sequence in context: A010782 A333111 A139584 * A113966 A164611 A316086 Adjacent sequences:  A064787 A064788 A064789 * A064791 A064792 A064793 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Oct 20 2001 STATUS approved

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Last modified August 8 14:04 EDT 2020. Contains 336298 sequences. (Running on oeis4.)