21143

Properties

Appears in sequences

• a(0) = 1, a(n) = 29*n^2 + 2 for n>0.at n=27A010019
• The array in A059216 read by antidiagonals in 'up' direction.at n=46A059217
• The array in A059216 read by antidiagonals in the direction in which it was constructed.at n=46A059234
• Primes such that prime(p) +- pi(p) are simultaneously prime.at n=34A065117
• Primes prime(k) such that prime(k)*k falls between twin primes.at n=14A080174
• Primes whose decimal representation is a valid number in base 5 and interpreted as such is again a prime.at n=33A090708
• Primes of the form 22*(n^2)+1.at n=15A117049
• Primes of the form p = prime(k+1) such that prime(k) = (prime(k+3)+prime(k-1))/2.at n=20A126239
• Primes p such that continued fraction of (1 + sqrt(p))/2 has period 16 : primes in A146339.at n=10A146361
• a(n) = 961*n + 1.at n=21A158414
• a(n) = 22*n^2 + 1.at n=31A158537
• Numbers k such that (2^k - k)*2^k + 1 is prime.at n=15A200816
• Consider two consecutive primes {p,q} such that P=2p+q and Q=2q+p are both prime. The sequence gives primes P.at n=42A248482
• Number of set partitions of [n] with alternating parity of elements.at n=12A274547
• a(n) is the least number such that d(a(n)) = d(R(a(n)))/n, where R(n) is the digit reverse of n and d(n) is the number of divisors of n.at n=13A284495
• Prime time primes on 6-digit clocks, second definition: primes of the form HMMSS where H, MM, SS are primes, H < 24, MM and SS < 60.at n=24A295013
• Primes whose index is divisible by the product of its digits.at n=29A306766
• Numbers k such that A001414(k^4+1) is divisible by k.at n=8A309558
• The prime numbers whose digit sum, adjacent digit sum concatenation, and adjacent digit difference concatenation are also primes.at n=50A330653
• Number of (binary) heaps where n is the sum of their length and the size of the element set [k].at n=14A373632