18840

Appears in sequences

• Let p1, p2 be first pair of consecutive primes with difference 2n; let p3, p4 be 2nd such pair; sequence gives "wadi" value p3-p1.at n=20A046728
• Numbers n such that n | sigma_13(n).at n=30A055717
• 3 times 10-gonal (or decagonal) numbers: a(n) = 3*n*(4*n-3).at n=40A152767
• prime(n)*( prime(n)-n ).at n=36A161522
• The fifth row of the ED2 array A167560.at n=6A167562
• G.f.: Sum_{n>=0} x^n * Sum_{k=0..n} binomial(n,k)^2 * x^k/(1-4*x)^k.at n=8A217666
• Numbers n such that sigma(n+sigma(n)) = 4*sigma(n).at n=40A246911
• Triangle in which row n consists of the coefficients in Sum_{m=0..n} x^m * Product_{k=m+1..n} (1-k*x), as read by rows.at n=40A248925
• Number T(n,k) of partitions of n into parts of exactly k sorts; triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=33A255970
• Sum of squares of numbers less than n that do not divide n.at n=38A276984
• Number of n X 3 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0, 1 or 4 neighboring 1's.at n=5A297677
• T(n,k)=Number of nXk 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0, 1 or 4 neighboring 1s.at n=33A297682
• Number of 6Xn 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 0, 1 or 4 neighboring 1s.at n=2A297686
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2 + (x + 47^2)^2 = y^2.at n=8A332000
• Numbers k such that A348215(k) = k.at n=30A348216