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 A158086 Number of occurrences of n as an entry in rows <= 2n of Losanitsch's triangle (A034851). 0

%I

%S 4,4,5,4,6,4,4,6,5,4,6,4,4,4,6,4,4,6,6,4,4,4,4,6,4,4,6,4,6,4,4,4,4,4,

%T 6,4,5,4,4,4,6,4,6,4,4,4,4,6,4

%N Number of occurrences of n as an entry in rows <= 2n of Losanitsch's triangle (A034851).

%C For n = 1 to 1000, the only values of a(n) are 4, 5, 6, 8, 10 and infinity.

%e a(4) = 5 because 4 occurs five times in Losanitsch's triangle: the first time at row 4, column 2, being the sum of the two 2's in the row above; and at column 1 of rows 7 and 8, which are symmetrically duplicated at row 7, column 6 and row 8, column 7.

%t (* The following assumes a[n, k] has already been defined to give Losanitsch's triangle; see for example the program given for A153046 *)

%t tallyLozOccs := Infinity; tallyLozOccs[n_Integer?Positive] := Module[{i, searchMax, tally}, i = 0; searchMax = 2n; tally = 0; While[i <= searchMax, tally = tally + Length[Select[Table[a[i, m], {m, 0, i}], # == n &]]; i++ ]; Return[tally]]; Table[tallyLozOccs[n], {n, 2, 50}]

%t (* this program also assumes a(n,k) has been defined for Losanitsch's triangle*)

%t Table[Length[Select[Flatten[Table[a[i,m], {i,0,2n}, {m,0,i}]],#==n&]], {n,2,50}] (* Wilfredo Lopez (chakotay147138274(AT)yahoo.com), Mar 18 2009 *)

%Y Cf. A003016, Number of occurrences of n as an entry in rows <= n of Pascal's triangle.

%K easy,nonn

%O 2,1

%A _Alonso del Arte_, Mar 12 2009

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Last modified November 15 14:06 EST 2019. Contains 329149 sequences. (Running on oeis4.)