21773

Properties

Appears in sequences

• Primes that remain prime through 4 iterations of function f(x) = 10x + 3.at n=8A023328
• A simple grammar.at n=10A052853
• Numbers k such that 10^k + 13 is prime.at n=17A095688
• Primes of the form f(n) = n^6 - 48*n^5 + 908*n^4 - 8603*n^3 + 42796*n^2 - 105410*n + 100823 listed by increasing value of n >= 0.at n=15A117091
• Prime numbers p such that p^3 - (p+1)^2 and p^3 + (p+1)^2 are both primes.at n=23A137476
• Prime p3 of the sequence A164063: a^b - c^d = p1 (A164063), where a, b, c, d are primes and a + b + c + d = p2 (A164064), where p2 is prime and conc(abcd) = p3 (concatenation of a, b, c , d) is also prime.at n=5A164065
• Primes of the form 5n^2 - 7.at n=14A201788
• Primes that are the sum of the squares of three integers that form an arithmetic sequence with difference 7.at n=9A227994
• Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 278", based on the 5-celled von Neumann neighborhood.at n=28A287488
• Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 278", based on the 5-celled von Neumann neighborhood.at n=29A287488
• Prime time primes (of the form HMMSS with primes H < 24 and MM, SS < 60) such that the corresponding number of seconds after midnight is also prime.at n=12A295000
• Primes p such that (p mod s) and (p mod t) are consecutive primes, where s is the sum of the digits of p and t is the product of the digits of p.at n=23A344127
• Primes p such that if q is the next prime, (p+q)/6 is a triangular number.at n=37A356293
• Primes p such that the sum and difference of the fourth power of the sum of 4 consecutive primes starting with p and the product of those primes are both prime.at n=10A389333
• Prime numbersat n=2443