95772

Appears in sequences

• Number of ways to arrange integers 1 through n so that the sum of each adjacent pair is prime, not counting reversals.at n=14A051239
• Number of ways of writing the numbers 1 .. n in a sequence so that the sum of any two adjacent numbers is a prime; reversing the sequence does not count as different.at n=14A064821
• a(n) is the number of essentially different ways in which the integers 1,2,3,...,n can be arranged in a sequence such that all pairs of adjacent integers sum to a prime number. Rotations and reversals are counted only once.at n=14A073452
• Expansion of -x*(x^6+3*x^5+2*x^4-2*x^3-4*x^2+4*x-1)/((1-x)^2*(1-2*x-x^2)^2).at n=13A111109
• a(n) = 13 + floor(Sum_{j=1..n-1} a(j)/2).at n=22A120140
• Number of permutations of 2 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/2)] (2-way heap).at n=6A178012
• Expansion of Product_{k>=1} 1/(1-x^k)^(k+(-1)^k).at n=22A258386