48516

Appears in sequences

• Even triangular numbers with prime indices.at n=33A034955
• a(0) = 9; for n>0, a(n) is determined by the rule that the concatenation of the leading terms of the difference triangle is the same as the concatenation of the digits of the sequence.at n=14A125004
• a(n) = m*(m+1)/2, where m = floor(n^(3/2)).at n=45A185541
• Triangular arithmetic on half-squares: b(n)*(b(n) - 1)/2 where b(n) = floor(n^2/2).at n=25A227970
• Triangular numbers that in base 2 have the same number of 0's and 1's.at n=33A345348
• a(n) = Sum_{k=1..n} k^2 * 4^(n-k).at n=8A368529
• Positive triangular numbers such that the two numbers before it and the two numbers after it are squarefree.at n=37A374503