31375

Appears in sequences

• Numbers k such that 6!*(2*k-7)!/(k!*(k-1)!) is an integer.at n=35A004786
• Numbers k that divide s(k), where s(1)=1, s(j)=21*s(j-1)+j.at n=42A014872
• T(n,0) + T(n,1) + ... + T(n,[ n/2 ]), T given by A027144.at n=13A027152
• Numbers k that divide 3^k + 2^k.at n=16A045576
• Numbers k that divide 6^k + 4^k.at n=38A045591
• Numbers n such that n | 11^n + 10^n + 9^n + 8^n + 7^n + 6^n + 5^n + 4^n + 3^n + 2^n.at n=27A057288
• Third row of Pascal-(1,6,1) array A081581.at n=36A081591
• Triangular numbers whose sum of aliquot divisors is a prime number.at n=20A083676
• Triangular numbers with only odd digits.at n=20A117960
• Triangular numbers with at most two distinct prime factors.at n=39A119663
• Cubeful numbers whose neighbors are also cubeful.at n=14A122692
• Square array T(n, k) = v(k, n)((1)), where v(n, q) = M*v(n-1, q), M = {{0, 1, 0}, {0, 0, 1}, {q^3, q^3, 0}}, with v(0, q) = {1, 1, 1}, read by antidiagonals.at n=49A173749
• Number of (n+3) X 6 0..1 matrices with each 4 X 4 subblock idempotent.at n=17A224563
• Triangular numbers of the form p*w, where p is a prime number and w is a prime power (A025475).at n=16A225674
• Triangular numbers which become primes when their rightmost digit is removed.at n=31A227936
• Primitive numbers in A229307.at n=25A229311
• Number of partitions of 2n into distinct parts < n.at n=36A231429
• Triangular numbers T such that both (T+2) and (T-2) are semiprimes.at n=36A242356
• a(n) = Sum_{d|n} max(d, n/d)^3.at n=24A297842
• a(n) = floor(C(n + 1/2)), where C = A000108.at n=10A303607