20540

Appears in sequences

• Square pyramidal numbers: a(n) = 0^2 + 1^2 + 2^2 + ... + n^2 = n*(n+1)*(2*n+1)/6.at n=39A000330
• Even square pyramidal numbers.at n=18A015222
• a(n) = s(1)*s(n) + s(2)*s(n-1) + ... + s(k)*s(n+1-k), where k = floor((n+1)/2), s = (odd natural numbers).at n=38A024598
• Consider the line segment in R^n from the origin to the point P=(1,2,3,...,n); let d = squared distance to this line from the closest point of Z^n (excluding the endpoints). Sequence gives d times P.P.at n=38A059774
• a(n) = (1/24)*(sigma_3(2*n-1) - sigma_1(2*n-1)).at n=39A081861
• Least area/6 of primitive Pythagorean triangles with odd leg 2n+1.at n=38A096893
• Structured rhombic dodecahedral numbers (vertex structure 9).at n=19A100157
• Sequence and first differences include all square numbers exactly once.at n=38A109678
• a(0)=0; then a(4*k+1)=a(4*k)+(4*k+1)^2, a(4*k+2)=a(4*k+1)+(4*k+3)^2, a(4*k+3)=a(4*k+2)+(4*k+2)^2, a(4*k+4)=a(4*k+3)+(4*k+4)^2.at n=39A115391
• Number of partitions of n such that the numbers of prime and composite parts differ by at least 1.at n=47A116450
• a(n) = n^3 + 114 * n.at n=25A122562
• 1/24 of product of three numbers: n-th prime, previous and following number.at n=20A127922
• Numbers k such that k^2 divides 21^k-1.at n=36A128401
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2 + (x+199)^2 = y^2.at n=8A129993
• Partial sums of [A080782^2].at n=38A164765
• The number of binary pattern classes in the (2,n)-rectangular grid with 3 '1's and (2n-3) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.at n=40A225972
• Number of blocks in a Steiner Quadruple System of order A047235(n+1).at n=25A228124
• Number of Sylvester classes of 3-packed words of degree n.at n=6A243659
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 342", based on the 5-celled von Neumann neighborhood.at n=38A269511
• Edge count of the n X n white bishop graph.at n=39A289179