191181domain: NAppears in sequencesList of pairs of primes in reverse order, starting at 1.at n=21A007796Number of (w,x,y,z) with all terms in {1,...,n} and w<2x+y+z.at n=21A212145Semiprimes that are the concatenation of a prime and the previous prime.at n=13A242102Expansion of Sum_{k>=1} ((1 + k * x^k)^k - 1).at n=29A327238