21125

Appears in sequences

• Least hypotenuse of n distinct Pythagorean triangles.at n=17A006339
• 10-gonal (or decagonal) pyramidal numbers: a(n) = n*(n + 1)*(8*n - 5)/6.at n=25A007585
• Numbers that are the sum of 2 nonzero squares in exactly 6 ways.at n=13A025289
• Numbers that are the sum of 2 nonzero squares in 5 or more ways.at n=19A025296
• Numbers that are the sum of 2 nonzero squares in 6 or more ways.at n=13A025297
• Numbers that are the sum of 2 distinct nonzero squares in exactly 6 ways.at n=13A025307
• Numbers that are the sum of 2 distinct nonzero squares in 5 or more ways.at n=17A025315
• Numbers that are the sum of 2 distinct nonzero squares in 6 or more ways.at n=13A025316
• a(n) = (n+5)^3 - n^3.at n=35A038867
• a(1)=9; if n = Product p_i^e_i, n > 1, then a(n) = Product p_{i+2}^{e_i+1}.at n=27A045972
• a(n) is smallest integral radius of circle centered at (0,0) having 8n-4 lattice points on its circumference; a(n)/2 is smallest half-integral radius circle centered at (1/2,0) having 4n-2 lattice points; a(n)/3 is smallest third-integral radius circle centered at (1/3,0) having 2n-1 lattice points.at n=17A046112
• 3-magic series constant.at n=4A052460
• Numbers of the form q1^b1 * q2^b2 * q3^b3 * q4^b4 * q5^b5 * ... where q1=5, q2=13, q3=17, q4=29, q5=37, ... (A002144) and b1 >= b2 >= b3 >= b4 >= b5 >= ....at n=14A054994
• Numbers n such that n | 11^n + 10^n + 9^n + 8^n + 7^n + 6^n + 5^n + 4^n + 3^n + 2^n.at n=25A057288
• Numbers k that can be expressed as k = w+x = y*z with w*x = k*(y+z) where w, x, y, and z are all positive integers.at n=33A057371
• Numbers n such that [A070080(n), A070081(n), A070082(n)] is an obtuse isosceles integer triangle with prime side lengths.at n=28A070135
• a(n)=n^2 times nearest cube to n^2.at n=13A077112
• Column 4 of an array closely related to A083480. (Both arrays have shape sequence A083479).at n=11A089574
• Numbers n for which there are exactly six k such that n = k + (product of nonzero digits of k).at n=16A096927
• Numbers n that are the hypotenuse of exactly 17 distinct integer-sided right triangles, i.e., n^2 can be written as a sum of two squares in 17 ways.at n=0A097239