18241

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 57.at n=33A020396
• T(n,1) + T(n,2) + ... + T(n,n), T given by A026703.at n=12A026710
• Number of partitions satisfying (cn(1,5) = cn(4,5) and cn(0,5) <= cn(2,5) and cn(0,5) <= cn(3,5)).at n=53A036810
• Numbers m such that the factorizations of m..m+4 have the same number of primes (including multiplicities).at n=10A045941
• Numbers m such that the factorizations of m..m+5 have the same number of primes (including multiplicities).at n=2A045942
• Expansion of (1+2*x+3*x^2)/((1-x)^3*(1-x^2)).at n=32A055232
• Composite numbers m such that phi(m)*sigma(m) is divisible by m-1.at n=28A065149
• a(n) = (prime(n)^2 + 1)/2.at n=41A066885
• Third row of Pascal-(1,5,1) array A081580.at n=32A081589
• a(n) = n*(n^2+3*n-1)/3.at n=37A084990
• (Prime(prime(n))^2+1)/2.at n=13A092773
• Pell pseudoprimes: odd composite numbers n such that P(n)-Kronecker(2,n) is divisible by n.at n=24A099011
• Least k such that prime(n)^2 divides binomial(2k,k).at n=42A110494
• (k^2)-th k-smooth number for k = prime(n).at n=18A133581
• Primitive subsequence of A111105.at n=31A137559
• 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, -1), (-1, 0, 0), (0, -1, 1), (1, 1, 0)}.at n=10A148667
• Partial sums of A151782.at n=30A151793
• Numerator of Sum_{k=1..n} k^4 / Product_{k=1..n} k^4.at n=13A181426
• Positions of 3's in A234323.at n=45A234804
• Numbers for which the cube of the sum of the digits is equal to the square of the product of their digits.at n=25A241846