21605

Appears in sequences

• a(n) = (6*n+1)*(6*n+5).at n=24A001513
• Second trisection of A061037.at n=48A142599
• a(n) = n*(n+1)*(5*n + 4)/6.at n=29A162147
• Quintisection A061037(5*n+2).at n=29A165248
• Number of toothpicks after n stages of 3-D toothpick structure defined in Comments.at n=31A170876
• Number of partitions of n+3 with largest inscribed rectangle having area <= n.at n=34A218624
• Permutation of natural numbers, a composition of A241909 and A064216: a(n) = A064216(A241909(n)).at n=42A243061
• a(n) = prime(n)^2 - 4*prime(n).at n=32A245034
• Nonprime numbers k of the form 4*m+1 such that Sum_{j=0..k-1} 2^j * binomial(3*j, j) == 1 (mod k).at n=33A373747