30227

Appears in sequences

• n-th 6k+1 prime times n-th 6k-1 prime.at n=18A048629
• Numbers k such that 2^k + 23 is prime.at n=9A057203
• Expansion of 1/( 1 - x / Product_{n>=1} (1-x^n) ).at n=13A067687
• Number of ways to represent n as a+b*(c+d*(e+f*(...x+y*(z)...))) in positive integers.at n=14A084978
• a(n) = prime(n)*prime(n+3).at n=38A090090
• Numbers n such that n and its reversal are distinct brilliant numbers (A078972).at n=30A097435
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (0, 1, 1), (1, 0, -1)}.at n=11A148289
• G.f.: exp( Sum_{n>=1} A002426(n)^2*x^n/n ), where A002426(n) is the central trinomial coefficients.at n=7A168598
• Sequence of pairwise relatively prime numbers of class P_6 (see comment in A275246).at n=20A275251
• Numbers such that the sum of the reverse of their aliquot parts is equal to the reverse of the sum of their aliquot parts.at n=39A278948
• Semiprimes where the sum of the digits equals the difference between the prime factors.at n=10A308821
• Numbers m such that Stern polynomial B(m,x) has no irreducible polynomial factors that themselves are Stern polynomials. The initial a(1) = 1 is included by convention.at n=41A389918