41943

Appears in sequences

• Lerch's function q_2(n) = (2^{phi(t)} - 1)/t where t = 2*n - 1.at n=12A001226
• a(n) is least k such that k and 7k are anagrams in base n (written in base 10).at n=24A023099
• a(n) = Sum_{k=m..n} T(k,n-k), where m = floor((n+1)/2); a(n) is the n-th diagonal-sum of left justified array T given by A027935.at n=27A027947
• Maximum cycle length in differentiation digraph for n-bit binary sequences.at n=40A038553
• Nearest integer to n^5/25.at n=15A061003
• Squarefree part of 2^n-1 : the smallest number such that a(n)*(2^n-1) is a square.at n=19A069112
• Let p be the n-th prime and let g be the order of 2 mod p (see A014664). Then if g is even, a(n) = p*(2^(g/2) - 1), otherwise a(n) = 2^g - 1.at n=11A135546
• Sequence equals its 4th differences shifted by one index.at n=13A137166
• a(n) = (2^A002326(n)-1)/(2*n+1).at n=12A165781
• a(n) = (1/n)*A204983(n).at n=24A204984
• a(n) = (1/n)*A204983(n).at n=49A204984
• (1/n)*A204991(n).at n=49A204992
• Carmichael quotients to base 2: a(n) = (2^lambda(2*n-1)-1)/(2*n-1), where lambda is the Carmichael lambda function (A002322).at n=12A329238
• Squarefree integers k such that x^4 - k*y^2 = 1 has a nontrivial solution.at n=41A356496