187578

Appears in sequences

• McKay-Thompson series of class 22a for Monster.at n=36A058569
• Triangular numbers for which the sum of the digits is a square.at n=29A117404
• G.f. satisfies: A(x) = x^2 + A(A(x))/x.at n=11A212380
• Number of (w,x,y,z) with all terms in {1,...,n} and |w-x| >= w + |y-z|.at n=35A212714
• Triangular numbers T such that sum of the factorials of digits of T is prime.at n=38A242831
• Triangular numbers representable as x*y+x+y such that x and y are triangular numbers, x>=y>0.at n=31A259745
• Triangular numbers representable as x*y+x+y such that x and y are triangular numbers, x>=y>1.at n=25A259746
• Numbers k such that the symmetric representation of sigma(k) has only two parts and they meet at the center of the Dyck path.at n=30A262259
• Triangular numbers (A000217) whose arithmetic derivative (A003415) is also a triangular number.at n=6A351130