A158464 - OEIS

A158464

Number of distinct squares in row n of Pascal's triangle.

1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1

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OFFSET

0,5

COMMENTS

It seems that some subset of terms in A055997 (A115599) gives the positions of 3's. E.g., we have a(9) = a(50) = a(289) = a(9801) = 3, but on the other hand, a(1682) = a(57122) = 2. - Antti Karttunen, Nov 03 2017

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..11111

Index entries for triangles and arrays related to Pascal's triangle

FORMULA

a(n) = Sum_{k=0..floor(n/2)} A010052(A007318(n,k));

a(A000290(n)) > 1 for n > 1.

EXAMPLE

a(8) = #{1} = 1;

a(9) = #{1,9,36} = 3.

MAPLE

A158464 := proc(n)

local sqset, k ;