20231

Properties

Appears in sequences

• a(n) = floor(n*phi^14), where phi is the golden ratio, A001622.at n=24A004929
• Values of A (the short leg) of a Pythagorean triangle with A and C (the hypotenuse) both prime and part of a twin prime.at n=35A051642
• Primes with 29 as smallest positive primitive root.at n=2A061733
• Primes p such that sum of squares of even-position digits equals the sum of squares of odd-position digits of p.at n=5A076168
• Starting positions of strings of three 6's in the decimal expansion of Pi.at n=13A083625
• a(n) = ceiling(((1*n^0 + 1*n^1 + 2*n^2 + 4*n^3)/(1*n^0 + 2*n^1 + 1*n^2))^2).at n=36A085505
• For p = prime(n), a(n) is the smallest N such that pN is a base-2 pseudoprime (that is, 2^(pN-1) = 1 mod pN).at n=50A086000
• Primes in which the unit place digit is 1 and the k-th most significant digit is prime (2,3,5,7) if k is prime else is composite (4,6,8,9,0).at n=26A089704
• Smallest n-digit prime in which the unit place digit is 1 and the k-th most significant digit is prime (2,3,5,7) if k is prime else is composite (4,6,8,9,0).at n=3A089705
• a(n) = n-th centered n-gonal number.at n=34A100119
• Primes dividing terms of A128358.at n=1A134360
• Primes congruent to 53 mod 59.at n=39A142780
• Primes congruent to 40 mod 61.at n=38A142838
• 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), (0, 1, -1), (0, 1, 1), (1, -1, 0)}.at n=9A148871
• a(n) = 70*n^2 + 1.at n=17A158734
• Primes of the form (p^2 - 1)/16 - p, where p is also a prime.at n=9A165616
• Lesser of twin primes p1 such that p1+(p2^2-p1^2) and p2+(p2^2-p1^2) are prime numbers.at n=28A174922
• Primes p of the form 4*k+3 such that p+2 is prime and p-1 is nonsquarefree.at n=22A175606
• Chen primes A109611(k) which have the same sum-of-digits as their index k.at n=37A176012
• Incorrect duplicate of A062343.at n=30A176254