20193

Appears in sequences

• Numbers k such that 40*R_k + 1 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=11A056681
• Sixth column (r=5) of FS(3) staircase array A062745.at n=14A062749
• The sum of a triangular array made from a negative 6-fold permutation product.at n=15A105156
• Number of positive integers <= 10^n that are divisible by no prime exceeding 11.at n=10A107352
• a(n) = prime(n) * Sum_{i=1..n} prime(i).at n=15A143215
• Number of n X n binary arrays symmetric under horizontal reflection with all ones connected only in a 11000-01100-00110-00011 pattern in any orientation.at n=13A147445
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, -1), (-1, 0, 1), (0, 1, 0), (1, -1, 0)}.at n=11A148126
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 1, 0), (0, 0, -1), (1, 0, 1)}.at n=10A148669
• a(n) is the only number m such that m = pi(1^(1/n)) + pi(2^(1/n)) + ... + pi(m^(1/n)).at n=8A171270
• a(n) = Sum_{i=0..n} digsum_5(i)^4, where digsum_5(i) = A053824(i).at n=34A231671
• Number of ASCII letter 'A' bytes that when compressed with zlib generate a new record longest compressed byte stream.at n=35A375585
• Expansion of e.g.f. (1/x) * Series_Reversion( x * (1 - x)^2 * exp(-x/(1 - x)^2) ).at n=4A380666