1194649

Appears in sequences

• Pseudoprimes whose prime factors do not divide any smaller pseudoprime.at n=26A084653
• Composite numbers j such that binomial(2*j,j) == 2^j (mod j).at n=9A084699
• Brilliant Sarrus numbers.at n=23A086837
• Least n-pseudoprime which is a power of a prime number; smallest prime-power pseudoprime to base n.at n=1A090096
• Least n-pseudoprime which is a power of a prime number; smallest prime-power pseudoprime to base n.at n=3A090096
• Least n-pseudoprime which is a power of a prime number; smallest prime-power pseudoprime to base n.at n=15A090096
• a(n) = (1 + 3^n - 2*3^(n/2))/4 if n is even, (1 + 3^n - 4*3^((n-1)/2))/4 if n odd.at n=13A107767
• a(n) = (A046717(n))^2 (starting with n=1).at n=6A120096
• Overpseudoprimes to base 2: composite k such that k = A137576((k-1)/2).at n=27A141232
• Pseudoprimes to base 2 that are not squarefree, including the even pseudoprimes.at n=0A158358
• Catalan pseudoprimes: odd composite integers n=2*m+1 satisfying A000108(m) == (-1)^m * 2 (mod n).at n=1A163209
• Squares n^2 that become prime after omitting all ones in their decimal expansion.at n=20A175983
• a(n) = ((3^(n-1) - 1)^2)/4.at n=7A238976
• Pseudoprimes to base 2 divisible by 1093^2.at n=0A247830
• Numbers n > 1 where all prime factors are Wieferich primes, i.e., terms of A001220.at n=2A270833
• The smallest square referenced in A237043 (Numbers n such that 2^n - 1 is not squarefree, but 2^d - 1 is squarefree for every proper divisor d of n.).at n=7A282631
• Numbers k having at least one prime factor p such that p^2 divides 2^(k-1) - 1.at n=4A291194
• Composite numbers k such that D(k) == 3 (mod k), where D(k) is the k-th central Delannoy number (A001850).at n=12A330203
• a(n) is the smallest n-gonal number that is a Fermat pseudoprime to base 2 (A001567), or -1 if no such number exists.at n=1A371759
• Strong pseudoprimes to base 2 that are not squarefree.at n=0A376304