113520

Appears in sequences

• a(n) = A050314(2n+1,1): column 1 of triangle.at n=31A050316
• Number of primitive (period n) periodic palindromes using exactly four different symbols.at n=15A056500
• a(n) = least natural number k such that the distance between (n, sigma(n)) and (n+k, sigma(n+k)) is an integer (i.e., k^2 + (sigma(n+k) - sigma(n))^2 is a square), if such k exists; 0 otherwise.at n=0A066790
• Number of (w,x,y,z) with all terms in {1,...,n} and w<|x-y|+|y-z|.at n=21A212568
• a(n) = Sum_{k=1..n} mu(k) * (floor(n/k)^4 - floor((n-1)/k)^4).at n=30A344597
• a(n) = Sum_{k=1..n} tau( (n/gcd(k,n))^n ).at n=39A373002
• a(n) is the number of imprimitive (periodic) 2n-bead balanced binary necklaces.at n=24A386946