41328

Appears in sequences

• a(n) = n^2*(2*n^2 - 1); also Sum_{k=0..n-1} (2k+1)^3.at n=12A002593
• Coefficient of x^6 in expansion of (1+x+x^2)^n.at n=13A005714
• Number of segments (and sides) created by diagonals of an n-gon in general position.at n=25A014628
• T(2n,n-2), T given by A027907.at n=6A027910
• Triangular numbers which are 8-almost primes.at n=4A076582
• a(1) = 1; for n > 1, a(n) = smallest triangular number which is n times another triangular number > 1, or -1 if no such number exists.at n=47A077672
• Triangular numbers > 0 with a prime signature that has not occurred earlier.at n=32A085076
• Convolution of triangular numbers with partition numbers.at n=19A086716
• a(n) = Fibonacci(n)*(2*Fibonacci(n)-1).at n=12A095122
• Structured truncated dodecahedral numbers.at n=13A100153
• Transform of n^3 by the Riordan array (1/(1-x^2), x).at n=23A105636
• Triangular numbers for which the sum of the digits is a heptagonal number.at n=34A117312
• Triangular numbers for which the sum of the digits equals the sum of the digits of the next triangular number.at n=13A117511
• Row sums of triangle A134392.at n=26A134393
• a(n)=2*Product[(1 + 4*Cos[k*Pi/n]^2)*(1 + 4*Sin[k*Pi/n]^2), {k, 1, Floor[(n - 1)/2]}] - Product[(1 + 4*Sin[k*Pi/n]^2), {k, 1, Floor[(n - 1)/2]}].at n=12A152190
• 1, followed by list of numbers n such that the number of strong primes and the number of weak primes are equal at the n-th prime.at n=25A175102
• a(n) = n(F(n+2) - 1) where F(n) is defined by A000045.at n=16A179023
• Triangular numbers k whose divisors can be partitioned into three disjoint sets whose sums are all sigma(k)/3.at n=22A206025
• Number of (w,x,y,z) with all terms in {0,...,n} and odd range.at n=16A212890
• Triangular arithmetic on half-squares: b(n)*(b(n) - 1)/2 where b(n) = floor(n^2/2).at n=24A227970