20176

Appears in sequences

• a(n) = n^2*(16*n^4-20*n^2+7)/3.at n=3A002594
• a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t = A008578 ({1} U primes).at n=38A023862
• Numbers k such that 7^k - 2 is a prime.at n=25A090669
• Structured tetragonal anti-prism numbers.at n=25A100182
• Numbers k such that 10^k + 5*R_k + 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=23A102938
• Number of permutations of length n which avoid the patterns 123 and 4312.at n=25A116699
• a(0) = a(1) = 1; for n >= 2, a(n) = a(n-1) + a(n-2) - (n-1) if that number is positive and not already in the sequence, otherwise a(n) = a(n-1) + a(n-2) + (n-1).at n=23A117822
• Determinants of 4 X 4 matrices of 16 consecutive primes.at n=35A118799
• a(n) = 1^n + 3^n + 5^n + 7^n.at n=5A134006
• Expansion of Product_{k >= 0} (1 + A147954(k)*x^k).at n=32A147955
• Monotonic ordering of set S generated by these rules: if x and y are in S then x^2+y^2-xy is in S, and 2 is in S.at n=24A192533
• Phi(n) values in A115921.at n=26A216381
• Recurrence a(n) = a(n-2) + n^M for M=5, starting with a(0)=0, a(1)=1.at n=7A231304
• Triangle read by rows: T(n,k) is the number of weighted lattice paths B(n) having a total of k uhd and uHd strings.at n=32A247294
• Number of weighted lattice paths B(n) having no uhd and no uHd strings.at n=14A247295
• Number of 6-cycles in the n X n knight graph.at n=15A289181
• Numbers k such that all digits in k are different and for each digit d it is true that k = d (mod sum of digits(k) - d).at n=22A306788
• Lower bounds for the maximum number of stable matchings in the stable marriage problem based on composing smaller instances.at n=13A357271
• Table read by antidiagonals: Place k points in general position on each side of a regular n-gon and join every pair of the n*(k+1) boundary points by a chord; T(n,k) (n >= 3, k >= 0) gives number of edges in the resulting planar graph.at n=33A367190