55660

Appears in sequences

• Numbers n such that 99*2^n-1 is prime.at n=36A050575
• Numbers k such that 3^k mod k = 3^k mod k^2.at n=28A125774
• Numbers k such that k^2 divides 3^k-1.at n=11A127103
• Consider a decimal number of k>=2 digits x = d_(k)*10^(k-1) + d_(k-1)*10^(k-2) + ... + d_(2)*10 + d_(1) and the transform T(x)-> (d_(k)+d_(k-1) mod 10)*10^(k-1) + (d_(k-1)+d_(k-2) mod 10)*10^(k-2) + ... + (d_(2)+d_(1) mod 10)*10 + (d_(1)+d(k) mod 10). Sequence lists the numbers x such that T(x) divides x.at n=19A244286
• a(n) = 27*(n - 6)^2 + 4*(n - 6)^3 = ((n - 6)^2)*(4*n + 3).at n=28A245032
• a(n) = (prime(n) - 7)^2 * (4*prime(n) - 1).at n=9A245035
• Number of length n+7 0..3 arrays with at most one downstep in every 7 consecutive neighbor pairs.at n=3A258729
• Number of length n+4 0..3 arrays with at most one downstep in every n consecutive neighbor pairs.at n=6A258734
• Positions of 4's in A347381.at n=53A347394
• G.f. A(x) satisfies A(x) = 1 + x^4*A(x)^4*(1 + x*A(x)).at n=25A365730
• Number of ternary strings of length n avoiding the substrings 00, 11, 22, 121, 212, 202.at n=22A373447