84060

Appears in sequences

• Numbers k such that 1*k + 1, 3*k + 1, 9*k + 1, 27*k + 1, 81*k + 1 are all primes.at n=9A112042
• Number of permutations of 2 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/4)] (4-way heap).at n=5A178014