21867

Appears in sequences

• Larger terms of the pairs (a < b) in the sequence {a,b}-> {Max[{a,b}]-Min[{a,b}],k*Min[{a,b}]} with k=3 and the first pair {a=1,b=2}. See A075256.at n=39A075258
• One-third of the number of n X n nonnegative integer arrays with every 3 X 3 subblock summing to 1.at n=22A145052
• a(n) = 16*n^2 - n.at n=36A157446
• a(n) = 841*n + 1.at n=25A158404
• a(n) = 26*n^2 + 1.at n=29A158549
• a(n) = 1369*n^2 - 37.at n=3A158743
• Number of triples (w,x,y) with all terms in {0,...,n} and w <= floor((x+y)/3).at n=39A212973
• Value of concatenation of all suffixes of binary representation of n.at n=21A241426
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 813", based on the 5-celled von Neumann neighborhood.at n=25A273640
• Numbers k such that k![10]-2 is prime, where k![10] is the ten-fold multifactorial.at n=62A283559
• Numbers k such that 9*10^k + 67 is prime.at n=18A294679
• a(n) = (2*n-3-(-1)^n)*(22*n^2-21*n+5*n*(-1)^n)/96.at n=36A298992
• G.f. A(x) satisfies: 1 = A(x) - x/(A(x) - 2^3*x/(A(x) - 3^3*x/(A(x) - 4^3*x/(A(x) - 5^3*x/(A(x) - 6^3*x/(A(x) - ...)))))), a continued fraction relation.at n=4A338633
• a(n) = 8*n^3 - 6*n - 1.at n=14A369922
• Numbers k such that sopfr(k + sopfr(k)) = sopfr(k) + sopfr(sopfr(k)), where sopfr = A001414.at n=27A376851
• Expansion of e.g.f. 1/(1 - arcsin(2*x))^(1/2).at n=6A385421