OFFSET
2,1
COMMENTS
For n = 1 to 1000, the only values of a(n) are 4, 5, 6, 8, 10 and infinity.
EXAMPLE
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.
MATHEMATICA
(* The following assumes a[n, k] has already been defined to give Losanitsch's triangle; see for example the program given for A153046 *)
tallyLozOccs[1] := 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}]
(* this program also assumes a(n, k) has been defined for Losanitsch's triangle*)
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 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Alonso del Arte, Mar 12 2009
STATUS
approved