26937

Appears in sequences

• Number of solutions to c(1)*prime(2) + ... + c(n)*prime(n+1) = 2, where c(i) = +-1 for i > 1, c(1) = 1.at n=23A022899
• Number of partitions of n with equal number of parts congruent to each of 1 and 2 (mod 5).at n=53A035556
• Denominators of continued fraction convergents to sqrt(499).at n=8A041953
• Composite numbers m such that phi(m)*sigma(m) is divisible by m-1.at n=33A065149
• L-th order palindromes with L > 2.at n=23A089381
• Let S(1)={1} and, for n>1 let S(n) be the smallest set containing x, x+1, 2x and 3x for each element x in S(n-1). a(n) is the number of elements in S(n).at n=14A123247
• Numbers n such that (n(n+1)/2) modulo sigma(n) = n.at n=13A232538
• Numbers n such that floor(antisigma(n) / sigma(n)) = floor(antisigma(n+1) / sigma(n+1)).at n=14A244666
• Number of (undirected) paths in the n-sun graph.at n=3A288706
• Composite numbers k coprime to 13 such that k divides A006190(k) - Kronecker(13,k).at n=28A327654
• Odd composite integers m such that A087130(m) == 5 (mod m).at n=40A335671
• Odd composite integers m such that U(m)^2 == 1 (mod m) and V(m) == 5 (mod m), where U(m) and V(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=5 and b=-1, respectively.at n=25A337628
• Odd composite integers m such that A052918(m-J(m,29)) == 0 (mod m) and gcd(m,29)=1, where J(m,29) is the Jacobi symbol.at n=34A340095
• Numbers k such that sigma(k)^2 is divisible by k-1.at n=28A344347