23143

Properties

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 74 ones.at n=30A031842
• Primes whose indices are the sum of the first n+1 Fibonacci numbers.at n=15A105554
• Prime numbers p such that p^3 - (p-1)^2 and p^3 + (p-1)^2 are also primes.at n=28A137474
• Primes of the form 88x^2+32xy+127y^2.at n=34A140630
• Ulam's spiral (WNW spoke).at n=38A143859
• Primes p such that p*floor(p/2) - 4 and p*floor(p/2) + 4 are prime numbers.at n=30A164622
• Partial sums of A027642.at n=33A173242
• a(n) = 12*n^2 - 2*n - 1.at n=44A185918
• Coefficient of x in the reduction by x^2 -> x+1 of the polynomial p(n,x) defined at Comments.at n=17A192965
• Number of 5-bead necklaces labeled with numbers -n..n not allowing reversal, with sum zero and first and second differences in -n..n.at n=22A209009
• Primes that are sum of both three and five consecutive primes.at n=30A211170
• Expansion of x^4*(1-7*x+17*x^2-18*x^3+11*x^4-5*x^5)/((1-x)^2*(1-3*x)^2*(1-3*x+x^2)^2).at n=11A219756
• Primes of the form T(n) + S(n) + C(n) + 1 where T(n), S(n) and C(n) are the n-th triangular, square and cube numbers.at n=6A228908
• Primes p with f(p), f(f(p)) and f(f(f(p))) all prime, where f(n) = prime(n) - n + 1.at n=18A235934
• Number of compositions of n with exactly six occurrences of the largest part.at n=18A243741
• Centered 14-gonal (or tetradecagonal) primes.at n=11A264821
• 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=21A295000
• Primes p such that (p+nextprime(p))/6 is prime and 6*p is the sum of two consecutive primes.at n=23A339775
• Irregular triangle read by rows: T(n,k) (n>=0) is the least prime such that T(n,k) + r*i (0 <= i < k) is an arithmetic progression of primes with first difference primorial(n), or 0 if no such prime exists.at n=51A350679
• Irregular triangle read by rows: T(n,k) (n>=0) is the least prime such that T(n,k) + r*i (0 <= i < k) is an arithmetic progression of primes with first difference primorial(n), or 0 if no such prime exists.at n=52A350679