20225

Appears in sequences

• Numbers k such that 2*3^k + 5 is prime.at n=27A057911
• Numbers that define integer Heronian triangles [prime(a(n)), prime(a(n)+1), A068965(n)] with area A068966(n).at n=23A068964
• Structured hexagonal diamond numbers (vertex structure 5).at n=24A100178
• Triangular matrix T, read by rows, that satisfies: T = D + SHIFT_LEFT(T^2) where SHIFT_LEFT shifts each row 1 place to the left and D is the diagonal matrix {1, 2, 3, ...}.at n=10A107667
• Column 0 of triangle A107667.at n=4A107668
• Matrix square of triangle A107667.at n=11A107670
• Number of partitions of n into parts that are odd or == +- 4 mod 10.at n=49A134157
• Number of simple graphs on n vertices with each component regular.at n=11A165647
• Number of partitions of n containing at least one part m-5 if m is the largest part.at n=38A212545
• Number of partitions p of n such that 2*min(p) is a part of p.at n=38A238589
• Concatenate n-th composite number with concatenation of its prime factors in ascending order.at n=10A245315
• a(n) = [x^n] (1/(1 - x)^n)*Sum_{k>=1} prime(k)*x^k.at n=8A293210
• T(n,k) = V(n,k)/k!, where V(n,k) = k^(n*k) - Sum_{t=1..k-1} binomial(k,t)*k^(n*(k-t))*V(n,t) for n, k >= 1; square array T read by upwards antidiagonals.at n=19A342202
• First index k where A366574(k) = n.at n=25A366724
• Number of integer compositions of n with no maximal runs of the form (k)^k for any k.at n=18A389508