21844

Appears in sequences

• Numerators in Taylor series for tan(x). Also from Taylor series for tanh(x).at n=6A002430
• Left diagonal of partition triangle A047812.at n=17A007044
• Barlow packings with group R3(bar)m(SO) that repeat after 6n+3 layers.at n=15A011954
• a(n) = a(n-1) + 2*a(n-2) + 2, for n>=3, where a(0)= 1, a(1)= 2, a(2)= 4.at n=14A026644
• Number of partitions of n into parts not of the form 17k, 17k+2 or 17k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 7 are greater than 1.at n=44A035963
• Numbers whose base-2 representation has exactly 14 runs.at n=7A043581
• Intrinsic 10-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.at n=24A060947
• a(n) = floor(log(n)*2^n/n).at n=16A065613
• a(n) = round(log(n)*2^n/n).at n=16A065614
• Partial sums of Jacobsthal gap sequence.at n=14A080610
• a(n) = (4/3)*(4^n - 1).at n=7A080674
• Expansion of x*(1+2*x)/((1+x)*(1-x)*(1-2*x)).at n=14A084639
• Expansion of (1+x-4*x^2) / ((1+x)*(1-4*x^2)).at n=15A087213
• a(1) = 4; then alternately add -4 and multiply by -2.at n=29A096406
• Expansion of (1 - 2*x + 2*x^2)/((1 - x^2)*(1 - 2*x)).at n=15A097072
• Expansion of (1-x+2*x^2)/((1+x)*(1-2*x)).at n=15A097073
• Expansion of (1+3x)/((1-x)(1-4x^2)).at n=13A097164
• Numerators of the coefficients in the Taylor expansion of sec(x) + tan(x) around x=0.at n=13A099612
• Expansion of x^3 / ((x-1)*(2*x-1)*(x^2-x+1)).at n=16A111927
• Expansion of -2*x*(-3-2*x+4*x^2) / ((x-1)*(2*x+1)*(2*x-1)*(1+x)).at n=14A120462