27403

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = A023532, t = (Lucas numbers).at n=19A024368
• Erroneous version of A024368.at n=18A025068
• Number of partitions in parts not of the form 15k, 15k+3 or 15k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 6 are greater than 1.at n=44A035957
• Numbers k such that lcm(1,2,3,...,k)/13 equals the denominator of the k-th harmonic number H(k).at n=29A112818
• Composite terms in A128288(n) = A023163(n)/3 for n>1.at n=5A128289
• Number of n X 4 1..2 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in nondecreasing order.at n=25A166805
• Numbers k such that the coefficient of x^k in the expansion of Product_{j>=1} (1 - x^j)^5 is zero.at n=31A302057
• a(n) is the least number k such that exactly fraction 1/n of the members of the reduced residue system mod k are prime, or 0 if there is no such k.at n=7A307711
• Numbers k such that both k and k + 3 are consecutive deficient numbers.at n=7A317049
• Odd composite integers m such that U(m)^2 == 1 (mod m) and V(m) == 4 (mod m), where U(m) and V(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=4 and b=-1, respectively.at n=32A337627
• Odd composite integers m such that A000032(3*m-J(m,5)) == 3*J(m,5) (mod m), where J(m,5) is the Jacobi symbol.at n=29A339724
• Odd composite integers m such that A000045(3*m-J(m,5)) == 1 (mod m), where J(m,5) is the Jacobi symbol.at n=34A340235