25425

Appears in sequences

• Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^9 in powers of x.at n=29A001487
• Expansion of e.g.f. 1/(6-exp(x)-exp(2*x)-exp(3*x)-exp(4*x)-exp(5*x)).at n=3A004703
• a(n) = n^2*(n^2 + 1)/2.at n=15A037270
• Smallest triangular numbers that contain the digits of n anywhere in their middle.at n=42A062829
• Triangular numbers which are the sum of two squares.at n=30A073613
• Terms of A073872 that do not change their position in the rearrangement; i.e., values of A073872(n) which equal n(n+1)/2.at n=17A073873
• z-value of the solution (x,y,z) to 3/(2n+1) = 1/x + 1/y + 1/z satisfying 0 < x < y < z, odd x, y, z and having the largest z-value. The x and y components are in A075260 and A075261.at n=10A075262
• Cupolar numbers: a(n) = (n+1)*(5*n^2 + 7*n + 3)/3.at n=24A096000
• Triangular numbers equal to the sum of a prime number with its index.at n=20A115886
• Triangular numbers for which the sum of the digits is a heptagonal number.at n=26A117312
• Hexagonal numbers with prime indices.at n=29A117961
• Triangular numbers composed of digits {2,4,5}.at n=2A119158
• Expansion of x*(-1+5*x-6*x^2+x^3) / ( (2*x-1)*(x^3-3*x^2+1) ).at n=20A122167
• Triangle, read by rows, where row n equals row n of matrix power A132844^n for n>=0, where triangle A132844 is defined by: A132844(n,k) = T( [(n+k)/2], k) for n>=k>=0.at n=28A132845
• Column 0 of triangle A132845.at n=7A132846
• Triangular numbers n*(n+1)/2 with n and n+1 composite, where number of prime factors in n > number of prime factors in n+1.at n=44A144523
• a(n) = sum of numbers from 1 to pi(n), where pi(n) = A007955(n).at n=14A184390
• a(n) = m*(m+1)/2, where m = floor(n^(3/2)).at n=36A185541
• Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 2,3,4,1,1,0,0 for x=0,1,2,3,4,5,6.at n=5A197790
• Row sums of the triangle A045975.at n=14A204558