26895

Appears in sequences

• a(n) = dot_product(1,2,...,n)*(6,7,...,n,1,2,3,4,5).at n=39A026046
• Numbers k such that tau(k) - tau(k+1) = 1.at n=29A068208
• Numbers k such that sigma(k^2-k-1) = k*(k+1).at n=33A069826
• Squarefree numbers k with largest prime factor = floor(sqrt(k)).at n=27A071311
• Odd composites (including 1 in the count) where the number 3 mod 4 equals the number 1 mod 4.at n=9A093181
• T(n,3) diagonal of triangle in A095693.at n=8A095694
• a(n) = (n+1)*(n+2)^2*(n+3)*(7*n^2 + 23*n + 20)/240.at n=8A114240
• Triangle H(n,j) (n=1,2,3,..., j=2,3,4,...) read by rows: let X(k,l,n) := Stirling2(n,k)*Stirling2(k,l) for 1<=k<=n and 1<=l<=k. Then H(n,j)= sum_{k+l=j, 1<=k<=n and 1<=l<=k} X(k,l,n).at n=57A136206
• Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.at n=8A145959
• a(n) = (8*n+3)*(8*n+5).at n=20A177065
• The Wiener index of the windmill graph D(6,n). The windmill graph D(m,n) is the graph obtained by taking n copies of the complete graph K_m with a vertex in common (i.e., a bouquet of n pieces of K_m graphs).at n=32A180577
• Number of compositions of n where the difference between largest and smallest parts equals 6 and adjacent parts are unequal.at n=16A214275
• Number of ways of writing n as the sum of 11 triangular numbers.at n=12A226255
• Number of nondecreasing -3..3 vectors of length n whose dot product with some other -3..3 vector equals n.at n=12A226335
• Positive integers whose square is the sum of 50 consecutive squares.at n=16A257781
• Numbers n such that the number of divisors of n+1 divides n and the number of divisors of n divides n+1.at n=6A272353
• Number of compositions (ordered partitions) of n into primes of form x^2 + y^2 (A002313).at n=49A282971
• Number of compositions (ordered partitions) of 2*n-1 into primes of form x^2 + y^2.at n=24A287148
• Number of nX3 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 0, 2 or 3 neighboring 1s.at n=6A296583
• Number of nX7 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 0, 2 or 3 neighboring 1s.at n=2A296587