256961domain: NAppears in sequencesp*(p+2)/3 where p and p+4 are primes.at n=36A181093The number of permutations of length n sortable by 2 prefix block transpositions.at n=32A228394Octagonal numbers (A000567) that are semiprimes (A001358).at n=28A259677Octagonal numbers (A000567) in which parity of digits alternates.at n=30A297647