434010domain: NAppears in sequencesa(1)=1; a(n) is the smallest integer > a(n-1) such that the sum of elements of the simple continued fraction for S(n)=1/a(1)+1/a(2)+...+1/a(n) equals n^2.at n=31A071183Products of 6 distinct primes that are sandwiched between twin prime numbers.at n=23A378097