88410

Appears in sequences

• a(n) = p(n)*(p(n)-1)/2 where p(n) = upper member of n-th pair of twin primes.at n=21A082669
• Numbers n such that the denominator of the 2n-th Bernoulli number is divisible by n but sum_{d|n} sigma(d)/phi(d) is not an integer.at n=28A099008
• a(n) = n*(n+1)*(n^2+n+1)/2.at n=20A110450
• Triangular numbers that are sums of two consecutive primes.at n=40A111163
• Triangular numbers all of whose digits are nonprimes.at n=38A111484
• a(n) = t(n)_t(n) where t() = triangular numbers A000217.at n=19A122628
• Number of (w,x,y,z) with all terms in {1,...,n} and |w-x| >= w + |y-z|.at n=29A212714
• 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=22A262259
• a(n) is the multiplicative inverse of A008514(n) modulo A008514(n+1).at n=14A334121
• Integers m such that A342805(m) = m+3.at n=37A342806
• Triangular numbers which are products of five distinct primes.at n=24A357590
• Square array read by antidiagonals upwards: T(i,j) is the smallest number m such that the symmetric representation of sigma, SRS(m), has maximum width 3, consists of i parts and has 2*j occurrences of maximum width 3 in its width pattern (row m of A341969).at n=13A377667