28421

Appears in sequences

• Positions of 5-digit terms in the continued fraction for Pi (3 is position 0).at n=3A048961
• Revrepfigits (reverse replicating Fibonacci-like digits): Numbers k whose reversal occurs in a sequence generated by starting with the k digits of a number and then continuing the sequence with a number that is the sum of the previous k terms.at n=12A097060
• Numbers n such that A229964(n) = 3.at n=26A229966
• Composite numbers k coprime to 13 such that k divides A006190(k-Kronecker(13,k)).at n=23A327653
• Composite numbers k coprime to 13 such that k divides A006190(k) - Kronecker(13,k).at n=29A327654
• Intersection of A327653 and A327654.at n=9A327655
• Odd composite integers m such that A006497(m) == 3 (mod m).at n=32A335669
• Odd composite integers m such that U(m)^2 == 1 (mod m) and V(m) == 3 (mod m), where U(m) and V(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=3 and b=-1, respectively.at n=22A337626
• 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=34A337627
• 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=32A339724
• 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=35A340235
• Denominators of the convergents to the supergolden ratio.at n=7A381125
• a(n) = Sum_{k=0..floor(n/3)} binomial(n+k-1,k) * binomial(n-k-1,n-3*k).at n=12A389375