22669

Properties

Appears in sequences

• Primes that are palindromic in base 2 (but written here in base 10).at n=38A016041
• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 23.at n=6A031611
• Number of true prime powers whose binary order, ceiling(log_2(p^x)), is n.at n=39A036380
• Expansion of 2*x^2/(1 - 2*x - 2*x^2 + sqrt(1 - 4*x - 4*x^2)).at n=10A052705
• Triangle T(n,k) (n>=0, 0 <= k <= n) read by rows giving number of underdiagonal lattice paths from (0,0) to (n,k) using only steps R=(1,0), V=(0,1) and D=(1,2).at n=53A071943
• Triangle of numbers relating two simple context-free grammars (A052709 and A052705).at n=44A073152
• Primes in which no digit is coprime to its neighbors.at n=30A088297
• Triangle in A071943 with rows reversed.at n=46A108073
• a(n) = a(n-1) + a(n-2) - floor( a(n-1)/2 ).at n=38A173510
• Primes that cannot become a different prime under any mapping of some single decimal digit <=> with some other single decimal digit.at n=2A180561
• Numbers k such that 2^(k-1) == 1 + b*k (mod k^2), where b divides k - 2^p for some integer p >= 0 and 2^p <= b.at n=34A186884
• Primes p with P(p+1) also prime, where P(.) is the partition function (A000041).at n=14A234900
• Primes p such that 2*p+1 is divisible by the sum of digits of p+1.at n=36A267542
• Primes p such that 2*p + 31 is a square.at n=13A269786
• Primes p that remain prime through 3 iterations of function f(x) = 6x - 1.at n=23A289109
• Numbers without a digit 1 with digits in nondecreasing order and the product of digits is a power of 6.at n=24A304392
• Primes in A338529/2.at n=15A338533
• Primes p whose reverse q is a semiprime, and of p+q and its reverse one is a prime and the other is a semiprime.at n=23A350781
• Prime numbers that are not repdigits with digits in nondecreasing order with the property that any nontrivial permutation of the digits gives a composite number.at n=27A364458
• Numbers k such that (9^k + 3^k + 1)/13 is prime.at n=10A374105