A255316 - OEIS

%I #7 Aug 02 2021 07:56:16

%S 3,3,5,3,5,7,5,7,5,7,11,5,7,11,13,3,5,7,11,13,3,5,7,11,13,17,3,5,7,11,

%T 13,17,19,5,7,11,13,17,19,5,7,11,13,17,19,23,5,7,11,13,17,19,23,3,7,

%U 11,13,17,19,23,3,7,11,13,17,19,23,29,3,7,11,13,17

%N Distinct terms in triangle A255313, table read by rows.

%H Reinhard Zumkeller, <a href="/A255316/b255316.txt">Rows n = 1..150 of triangle, flattened</a>

%e See A255313.

%t (* A is A088643 *)

%t A[n_, 1] := n;

%t A[n_, k_] := A[n, k] = For[m = n - 1, m >= 1, m--,

%t      If[PrimeQ[m + A[n, k - 1]] &&

%t      FreeQ[Table[A[n, j], {j, 1, k - 1}], m], Return[m]]];

%t T[n_] := T[n] = Union[2 MovingAverage[

%t      Table[A[n+1, k], {k, 1, n+1}], {1, 1}]];

%t Array[T, 20] // Flatten (* _Jean-François Alcover_, Aug 02 2021 *)

%o (Haskell)

%o import Data.List (nub, sort)

%o a255316 n k = a255316_tabf !! (n-1) !! (k-1)

%o a255316_row n = a255316_tabf !! (n-1)

%o a255316_tabf = map (sort . nub) a255313_tabl

%Y Cf. A255313, A255395 (row lengths), A255427 (row products).

%K nonn,tabf

%O 1,1

%A _Reinhard Zumkeller_, Feb 22 2015