30865405domain: NAppears in sequencesp*(p+1)*(p+2)/6 where (p,p+2) are twin primes.at n=25A126249Tetrahedral numbers k*(k+1)*(k+2)/6 such that exactly two of k, k+1, and k+2 are prime.at n=27A152916a(n) is the smallest tetrahedral number with binary weight n.at n=20A359317