25585

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=42A000330
• Odd square pyramidal numbers.at n=21A015221
• a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = floor(n/2), s = (odd natural numbers).at n=41A025112
• a(n) = Sum_{k=1..n, gcd(n,k) = 1} k^2.at n=42A053818
• 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=41A059774
• Numbers that are sums of 2 or more consecutive squares in more than 1 way.at n=33A062681
• Sum of next n squares.at n=9A072474
• d(n,s) = number of perfect matchings on {1, 2, ..., n} with s short pairs.at n=40A079267
• Sequence and first differences include all square numbers exactly once.at n=41A109678
• Square array of numbers associated to the recurrences b(k) = b(k-1) + n*b(k-2); array T(n,k), read by descending antidiagonals, for n, k >= 0.at n=30A110112
• a(n) = Sum_{k=1..phi(n)} k*t(k), where t(k) is the k-th positive integer which is coprime to n and phi(n) is the number of positive integers which are <= n and are coprime to n.at n=42A135324
• Partial sums of [A080782^2].at n=41A164765
• Square pyramidal numbers which are sums of three consecutive primes.at n=1A167807
• 7 times hexagonal numbers: a(n) = 7*n*(2*n-1).at n=43A195320
• Coefficients of a generalized Jaco-Lucas polynomial (odd indices) read by rows.at n=40A200073
• a(n) = n*(1 + n)*(3 - 4*n + 4*n^2)/6.at n=13A213840
• Sum of the squared parts of the partitions of n into exactly two parts.at n=42A226141
• Number of blocks in a Steiner Quadruple System of order A047235(n+1).at n=27A228124
• a(n) = n*(2*n + 1)*(4*n + 1)/3.at n=21A258582
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 249", based on the 5-celled von Neumann neighborhood.at n=31A271014