21561

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 MFS = ZSM-57 H1.5[Al1.5Si34.5O72] starting with a T1 atom.at n=13A019170
• Number of symmetric types of (3,2n)-hypergraphs under action of complementing group C(3,2).at n=40A055780
• Expansion of (1 + 10*x + 20*x^2 + 10*x^3 + x^4)/(1-x)^5.at n=10A160747
• a(n) = ((3 + 2*sqrt(2))*(3 + sqrt(2))^n + (3 - 2*sqrt(2))*(3 - sqrt(2))^n)/2.at n=6A163606
• Numbers n such that n+/-2 and n^2+/-2 are all primes.at n=17A189051
• Number of tilings of a 9 X n rectangle using integer-sided rectangular tiles of area 9.at n=21A220126