23541

Appears in sequences

• a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = (1, p(1), p(2), ...).at n=31A024479
• a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = (1, p(1), p(2), ...).at n=30A025099
• Numerators of continued fraction convergents to sqrt(476).at n=6A041908
• Numbers n such that sigma(n+1)-sigma(n) = -sigma(n)/d(n), where d(n) denotes the number of divisors of n.at n=8A066177
• Numbers with 5 distinct digits {1,2,3,4,5} such that all adjacent digits (as well as first and last digits) are coprime.at n=19A104972
• Values of x in x^2 - 49 = 2*y^2.at n=14A106525
• Number of parts that are multiples of 3 in all partitions of n.at n=34A116635
• Number of n-node triangulations of the Klein bottle N_2 in which every node has degree >= 4.at n=4A129047
• Nonnegative values x of solutions (x, y) to the Diophantine equation x^2 + (x+84847)^2 = y^2.at n=16A201917
• Composite squarefree numbers n such that p(i)-9 divides n+9, where p(i) are the prime factors of n.at n=43A225709
• Final elements in rows when A322050 is displayed as a triangle.at n=12A322048
• a(n) is the smallest number > 1 whose base n digits yield the original number when added and multiplied left to right; or 0 if no such number exists.at n=47A334916
• Numbers which are the product of two S-primes (A057948) in exactly three ways.at n=20A343828