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A256507
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Triangle read by rows, giving in triangle A256946 the positions of n-th's row terms in row n+1.
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2
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1, 4, 7, 1, 2, 5, 7, 8, 11, 12, 14, 1, 2, 3, 6, 7, 9, 11, 12, 13, 16, 17, 19, 20, 22, 23, 1, 2, 3, 4, 7, 8, 10, 11, 13, 14, 16, 17, 18, 19, 22, 23, 24, 26, 27, 28, 30, 31, 33, 34, 1, 2, 3, 4, 5, 8, 9, 10, 12, 13, 14, 16, 17, 19, 20, 22, 23, 24, 25, 26, 29
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OFFSET
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1,2
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COMMENTS
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T(n,k) = k for k = 1..n;
T(n,n+1) = n + 3;
T(n,n*(n+2)) = (n+2)^2 - 2.
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LINKS
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EXAMPLE
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. ---+--------------------+--------------------------------------
. 1 | 1,4,7 | [1, 2, 3]
. 2 | 1,2,5,7,8,11,12,14 | [1,4, 5, 2,6, 7,3, 8]
. 3 | 1,2,3,6,7,9,11,... | [1,4,9,10,5,11,2,6,12,13,7,3,14,8,15] .
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MATHEMATICA
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row[n_] := (* row of A256946 *) row[n] = SortBy[Range[n(n+2)], If[IntegerQ[ Sqrt[#]], 0, N[FractionalPart[Sqrt[#]]]]&];
T[n_, k_] := FirstPosition[row[n+1], row[n][[k]]][[1]];
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PROG
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(Haskell)
import Data.List (elemIndex); import Data.Maybe (fromJust)
a256507 n k = a256507_tabf !! (n-1) !! (k-1)
a256507_row n = a256507_tabf !! (n-1)
a256507_tabf = zipWith (\us vs ->
map ((+ 1) . fromJust . (`elemIndex` vs)) us)
a256946_tabf $ tail a256946_tabf
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CROSSREFS
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KEYWORD
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nonn,tabf
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AUTHOR
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STATUS
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approved
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