31541

Properties

Appears in sequences

• Values of A (the short leg) of a Pythagorean triangle with A and C (the hypotenuse) both prime and part of a twin prime.at n=37A051642
• Primes whose digits can be rearranged to give the initial terms of the decimal expansion of Pi.at n=7A052493
• Prime number spiral (clockwise, South spoke).at n=29A054566
• Primes of the form perfect_power(n)+n.at n=25A075781
• G.f. satisfies: A(x) = G(x)*A(x^3*G(x)^2) where G(x) is the g.f. of the Motzkin numbers (A001006).at n=12A120895
• The lesser of twin primes p such that p*q+a+b+c are also the lesser of twin primes, (p and q are twin primes, p+2=q, a=p-1,b=(p+q)/2,c=q+1).at n=26A168536
• The Collatz iteration of these primes produces only even numbers, primes and 1.at n=47A177000
• 1/4 the number of (n+1) X (n+1) 0..3 arrays with no 2 X 2 subblock having sum 6.at n=1A183793
• 1/4 the number of (n+1)X3 0..3 arrays with no 2X2 subblock having sum 6.at n=1A183795
• T(n,k) = 1/4 the number of (n+1) X (k+1) 0..3 arrays with no 2 X 2 subblock having sum 6.at n=4A183802
• The number of permutations of length n sortable by 2 prefix block transpositions.at n=19A228394
• Primes p such that q = p^2 + 10 and q^2 + 10 are also prime.at n=35A243368
• Primes of form n^2 + 14641.at n=15A256839
• Denominators of upper primes-only best approximates (POBAs) to Pi; see Comments.at n=20A265811
• Primes p such that the sum of the squares of digits of p equals the sum of digits of p^2.at n=9A290972
• Number of Aut(G)-orbits on G-characters that come from Riemann surfaces of genus n.at n=35A347373
• Primes that can be represented as k*R(k) + 1, where R(k) is the reverse of k.at n=41A372197
• Start the sequence S with a(1) = 1008973 and extend S with a(n)/2 when a(n) is even, otherwise with a(n) + the smallest prime not yet added.at n=11A388141
• Prime numbersat n=3394