Decomposition of A005244
A self-generating sequence: start with 2 and 3, take all products of any 2 previous elements, subtract 1 and adjoin them to the sequence.
Decomposition of Nontotients
Nontotients: even n such that phi(m) = n has no solution.
Decomposition of Noncototients
Noncototients: n such that x - phi(x) = n has no solution.
Decomposition of A005279
Numbers having divisors d,e with d < e < 2d.
Decomposition of Niven numbers
Niven (or Harshad) numbers: numbers that are divisible by the sum of their digits.
Decomposition of A005381
Numbers n such that n and n-1 are composite.
Decomposition of A005382
Primes p such that 2p-1 is also prime.
Decomposition of A005383
Numbers n such that both n and (n+1)/2 are primes.
Decomposition of Sophie Germain primes
Sophie Germain primes p: 2p+1 is also prime.
Decomposition of Safe primes
Safe primes p: (p-1)/2 is also prime.