21880

Appears in sequences

• a(n) is the starting position of the first occurrence of a string of at least n consecutive digits '6' in the decimal expansion of Pi.at n=3A050285
• Intrinsic 10-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.at n=25A060947
• Starting positions of strings of three 6's in the decimal expansion of Pi.at n=14A083625
• Starting positions of strings of four 6's in the decimal expansion of Pi.at n=0A083626
• Expansion of g.f.: (1+2*x^3+2*x^6)/((1-x)*(1-x-x^2+x^3-x^4-x^5+x^6)).at n=20A084683
• a(n) is the starting position of the first occurrence of a string of exactly n 6's in the decimal expansion of Pi.at n=3A096760
• Right edge of the triangle in A033291.at n=39A192736
• a(n) = a(n-2) + a(n-1) + floor(n/2) + 1 for n > 1 and a(0)=0, a(1)=1.at n=19A215005
• a(n) = smallest number greater than n, equal to the determinant of the circulant matrix formed by its base-n digits.at n=39A219357
• Number of defective 4-colorings of an n X 5 0..3 array connected horizontally, vertically, diagonally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..3 order.at n=9A229575
• 30-gonal numbers: a(n) = n*(14*n-13).at n=40A254474
• Expansion of x^2*((1 - 12*x + 50*x^2 - 76*x^3 + 42*x^4 - 48*x^5 + 32*x^6)/(1 - 4*x)^4 + 4*x^2/(1 - 4*x)^(5/2)).at n=8A260346
• Positive numbers k such that k^2 - 1 divides 8^k - 1.at n=49A272062
• Number of n X 2 0..1 arrays with exactly n+2-2 having value 1 and no three 1s forming an isosceles right triangle.at n=17A272952
• Analog of Motzkin sums for Coxeter type D.at n=9A290380
• Number of partitions p of n such that (1/5)*max(p) is a part of p.at n=49A363068