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

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, 6, 4, 5, 4, 4, 4, 6, 4, 6, 4, 4, 4, 4, 6, 4

Offset

2,1

Comments

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

Links

Table of n, a(n) for n=2..50.

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

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

Sequence in context: A046593 A158935 A226446 * A364995 A195783 A376178

Adjacent sequences: A158083 A158084 A158085 * A158087 A158088 A158089

Keyword

easy,nonn

Author

Alonso del Arte, Mar 12 2009

Status

approved