52975

Appears in sequences

• Doubly triangular numbers: a(n) = n*(n+1)*(n^2+n+2)/8.at n=25A002817
• Triangular numbers with sum of digits = 28.at n=10A068132
• Hexagonal numbers for which the sum of the digits is also a hexagonal number.at n=33A117062
• Hexagonal numbers with prime indices.at n=37A117961
• Numbers k such that k-1 and k+1 are each the product of exactly 7 primes, counted with multiplicity.at n=13A157487
• a(n) = A185128(n) - A185129(n).at n=15A185253
• Triangular numbers whose sum of triangular divisors is also triangular and greater than 1.at n=3A209310
• Least triangular number t such that t = prime(n)*triangular(m) for some m>0, or 0 if no such t exists.at n=37A225503
• Least triangular number of the form p*triangular(n) where p is a prime number, or 0 if no such triangular number exists.at n=25A225789
• Triangular numbers which become primes when their rightmost digit is removed.at n=37A227936
• The first of two consecutive triangular numbers the sum of which is equal to the sum of two consecutive prime numbers.at n=21A298462
• Numbers k such that k and k+1 have the same sum of 5-smooth divisors.at n=35A355713