21679

Appears in sequences

• Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite NES = NU-87 H4[Al4Si64O136].nH2O starting with a T1 atom.at n=13A019202
• Strong pseudoprimes to base 58.at n=19A020284
• Neither square nor square + prime.at n=20A020495
• a(n) = C(n+2, 2) + C(n+2, 3) + C(n+2, 4) + C(n+2, 5).at n=18A027660
• a(n) = n*(3*n^2 + 3*n + 1).at n=19A249354
• Odd numbers which are not squares and cannot be written as a sum of a prime and a square.at n=5A308516
• a(n) = n * (binomial(n + 1, 3) + 1).at n=19A329523
• Cogrowth sequence of the 12-element dicyclic group Dic12 = <S,T | S^6, T^4, STST^3, S^3T^2>.at n=18A377656
• Number of sensed planar maps with n vertices and 2 faces.at n=9A380237