218685

Appears in sequences

• Numbers k such that k*(k+1)/2 + 1 is a square.at n=14A006451
• a(n) = (1/2) * (5*P(n+1) + P(n) - 1), where P(k) are the Pell numbers A000129.at n=13A098586
• Numbers k such that triangular(k)+1 is a square and triangular(k)+2 is a prime.at n=5A226071
• Numbers k such that the distance between the k-th triangular number and the nearest square is at most 1.at n=27A229083
• Numbers k such that the distance between the k-th triangular number and the nearest square is exactly 1.at n=21A229131