1413721

Appears in sequences

• Square triangular numbers: numbers that are both triangular and square.at n=5A001110
• a(n) = n^2*(2*n^2 - 1); also Sum_{k=0..n-1} (2k+1)^3.at n=29A002593
• Squares (A000290) which are also hexagonal numbers (A000384).at n=2A046177
• Numbers that are n-gons for three or more n's, where n=3,4,5,...,16.at n=17A062712
• Smallest number that is centered polygonal in exactly n ways.at n=29A063773
• a(n) = A073145(n)^2.at n=22A073702
• Nontrivial binomial coefficients which are perfect powers (A001597).at n=4A075760
• a(n) = 3*a(n-1) + 3*a(n-3) + a(n-4).at n=12A089931
• Area of n-th triple of hexagons around a triangle.at n=6A092936
• Square numbers which equal a triangular number times an odd number between 1 and 15.at n=17A094973
• Sum of the areas of the first n+1 Pell triangles.at n=9A096979
• Numbers which are powerful(1) (A001694) and triangular at the same time.at n=5A113938
• Triangle T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = Product_{j=1..n} (1 - ChebyshevT(j, k+1)^2), b(n, 0) = n!, and m = 2, read by rows.at n=16A156645
• Triangle T(n, k, m) = b(n,m)/(b(k,m)*b(n-k,m)), where b(n, k) = Product_{j=1..n} (1 - ChebyshevT(j, k+1)^2), b(n, 0) = n!, and m = 2, read by rows.at n=19A156645
• Perfect squares that are a product of two distinct triangular numbers.at n=13A169836
• A204512(n)^2 = floor[A055872(n)/8]: Squares such that appending some digit in base 8 yields another square.at n=11A204504
• Number of nX6 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 0 1 1 vertically.at n=8A208116
• Square triangular numbers that can be expressed as sums of a positive square number and a positive triangular number. Intersection of A182427 and A214937.at n=1A218273
• Triangular numbers representable as triangular(x)*triangular(y)+1.at n=32A226389
• Squares not divisible by 10 with digits d_1, d_2, ... d_k such that d_1^2 + ... + d_k^2 is a square.at n=40A254959