4192254

Appears in sequences

• Number of aperiodic binary strings of length n; also number of binary sequences with primitive period n.at n=22A027375
• Row sums of triangle T(m,n) = number of solutions to 1 <= a(1) < a(2) < ... < a(m) <= n, where gcd(a(1), a(2), ..., a(m), n) = 1, in A020921.at n=21A038199
• Number of primitive (aperiodic) words of length n which contain exactly two different symbols.at n=21A056267
• Number of primitive (aperiodic) palindromes using a maximum of two different symbols.at n=43A056458
• Number of primitive (aperiodic) palindromes using exactly two different symbols.at n=43A056463
• Number of triangles similar to their n-th pedal, and not similar to any k-th pedal for k < n.at n=10A102536
• a(n) = 4^n-2^n-2.at n=10A170940
• a(1)=1. For n>1, a(n) equals the smallest number > a(n-1) of the form a(k) U j U a(k) U j, where U represents concatenation (written in decimal) of the binary representation of the arguments, where 1 <= k < n, and j = {0} or {1}.at n=13A175335
• a(1)=1. For n>1, a(n) equals the smallest number > a(n-1) of the form a(k) U j U a(k) U j, where U represents concatenation (written in decimal) of the binary representation of the arguments, where 1<=k < n, and j = {0} or {1} or {}.at n=34A175336
• a(n) = AP(n) is the total number of aperiodic k-palindromes of n, 1 <= k <= n.at n=43A179781