20879

Properties

Appears in sequences

• Prime(n) and prime(n+2) use the same digits.at n=27A069794
• Solve 2^n - 2 = 7(x^2 - x) + (y^2 - y) for (x,y) with x>0, y>0; sequence gives value of x.at n=31A076632
• Expansion of (1-x) / (1+x^2+2*x^3).at n=30A078033
• a(n+3) = 2a(n+2) - 3a(n+1) + 2a(n); a(0) = 1, a(1) = 1, a(2) = 0.at n=31A105578
• Expansion of 1/((1-3x*c(x))(1-x^2*c(x))), c(x) the g.f. of A000108.at n=7A117376
• a(n) = 9 + floor( Sum_{j=1..n-1} a(j)/3 ).at n=27A120154
• Primes congruent to 17 mod 61.at n=36A142815
• 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, 0), (-1, 1, 0), (0, 1, -1), (0, 1, 1), (1, -1, 0)}.at n=9A148878
• Primes of the form 4*n^2 + 2*n -1.at n=35A155737
• Primes p such that (p-7)/8 and 8p + 7 are both prime.at n=23A158238
• Primes in A161190.at n=28A161191
• Consecutive pairs of prime point sums in A161191 (includes triples).at n=13A161192
• Primes that are the sum of all composite numbers in-between prime numbers p(n) and p(n+2).at n=18A174521
• Primes of form n^4 + n^2 - 1.at n=5A174819
• Primes p such that 2p+1, 3p+2 and 5p-2 are also primes.at n=20A178068
• Primes of the form 43*n^2 + 3*n + 1.at n=34A185658
• G.f. satisfies: A(x) = Sum_{n>=0} x^(n^2)*A(x)^(n^4).at n=9A191814
• Primes of the form 6n^2 - 7.at n=22A201792
• Primes of the form n^2-n-1 (for some n) such that p^2-p-1 is also prime.at n=17A237642
• Number of partitions of n containing m(2) as a part, where m denotes multiplicity.at n=41A240487