41905

Appears in sequences

• a(n) = n^2*(n^2 + 1)/2.at n=17A037270
• Triangular numbers with internal digits also forming a triangular number.at n=37A069702
• The terms of A073213 (sums of two powers of 17) divided by 2.at n=12A073221
• Triangular numbers which are the sum of two squares.at n=38A073613
• Terms of A073872 that do not change their position in the rearrangement; i.e., values of A073872(n) which equal n(n+1)/2.at n=20A073873
• Triangular numbers whose external digits as well as internal digits form triangular numbers.at n=26A077368
• Triangular numbers equal to the sum of a prime number with its index.at n=24A115886
• Eigenvector of triangle A119245, so that a(n) = Sum_{k=0..floor(n/2)} A119245(n,k)*a(k).at n=9A119244
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (0, 0, -1), (1, 0, -1), (1, 0, 1)}.at n=10A149087
• a(n) = (2*n^3 + 5*n^2 - 17*n)/2.at n=33A162259
• Row sums of the triangle A045975.at n=16A204558
• Number of 2 X 2 matrices with all terms in {0,1,...,n} and even trace.at n=16A210378
• Triangular numbers that are hypotenuse and a leg of a Pythagorean triple.at n=37A213188
• The number of distinct lines defined by an n X n X n grid of points.at n=5A222267
• Triangular numbers which have one or more occurrences of exactly five different digits.at n=31A241788
• a(n) = (n^2 + (n+1)^2)*(n^2 + (n+1)^2 + 2*n*(n+1)).at n=8A272850
• a(n) = (A278399(n)^2 + A278400(n)^2)/2.at n=40A278420
• Composite numbers n such that E(n+1)+1 is divisible by n, where E(n) is the n-th Euler number (A122045).at n=26A287934
• Chessboard rectangles sequence (see Comments), also A037270 interleaved with A163102.at n=34A317714
• Number of compositions of n containing no part p of multiplicity p.at n=17A336269