23821

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=41A000330
• Odd square pyramidal numbers.at n=20A015221
• 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=40A024598
• 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=40A059774
• a(n) = (1/24)*(sigma_3(2*n-1) - sigma_1(2*n-1)).at n=41A081861
• Least area/6 of primitive Pythagorean triangles with odd leg 2n+1.at n=40A096893
• Structured rhombic dodecahedral numbers (vertex structure 9).at n=20A100157
• Sequence and first differences include all square numbers exactly once.at n=40A109678
• 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=41A115391
• 1/24 of product of three numbers: n-th prime, previous and following number.at n=21A127922
• Let P(A) be the power set of an n-element set A. Then a(n) = the number of pairs of elements {x,y} of P(A) for which either 0) x and y are disjoint and for which either x is a subset of y or y is a subset of x, or 1) x and y are intersecting but for which x is not a subset of y and y is not a subset of x, or 2) x = y.at n=8A134045
• Sum of squares until integer log : sopfr(n). Or also, s(s+1)(2s+1)/6 where s=sopfr(n).at n=40A136135
• a(n) = 7*n*(2*n + 1).at n=41A195026
• Number of (w,x,y,z) with all terms in {1,...,n} and w > harmonic mean of {x,y,z}.at n=14A212105
• Minimal sum s of n distinct squares such that s is divisible by n.at n=40A215574
• 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=42A225972
• Number of squares formed from a square composed of p^2 unit squares where p is n-th prime.at n=12A262247
• 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=40A269511
• Edge count of the n X n white bishop graph.at n=41A289179
• 31-gonal numbers: a(n) = n*(29*n-27)/2.at n=41A360488