21126

Appears in sequences

• a(n) is the concatenation of n and 6n.at n=20A009440
• Shallit sequence S(3,13), a(n)=[ a(n-1)^2/a(n-2)+1 ].at n=6A010921
• Expansion of Sum_{n>=0} (q^n / Product_{k=1..n+5} (1 - q^k)).at n=32A035301
• McKay-Thompson series of class 14A for Monster.at n=16A058497
• Number of 3 X n (0,1) matrices such that each row and each column is nondecreasing or nonincreasing.at n=20A086113
• Multiples of 3018.at n=6A086746
• McKay-Thompson series of class 14A for the Monster group with a(0) = 1.at n=16A134782
• G.f.: A(x) = Sum_{n>=0} (-1)^n * (1 -x -2^n*x^2)^(-1) * log(1 -x -2^n*x^2)^n / n!.at n=8A136509
• 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, 0), (-1, 0, 1), (0, 1, -1), (1, -1, 0), (1, 0, 1)}.at n=9A148934
• Numbers n such that 30n+{11, 13, 17, 19, 23} are 5 consecutive primes.at n=25A182279
• Number of (n+1) X 3 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock equal to two.at n=3A205830
• Number of (n+1)X5 0..2 arrays with the number of clockwise edge increases in every 2X2 subblock equal to two.at n=1A205832
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the number of clockwise edge increases in every 2X2 subblock equal to two.at n=11A205836
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the number of clockwise edge increases in every 2X2 subblock equal to two.at n=13A205836
• Number of n X 2 0..1 arrays with rows, columns and antidiagonals unimodal and diagonals nondecreasing.at n=24A223764
• Expansion of ( 3-2*x-2*x^2 ) / ( 1-5*x+2*x^2+3*x^3 ).at n=6A275634
• Numbers k whose sum of divisors equals the sum of divisors of 2*k-1.at n=10A289738