21059

Properties

Appears in sequences

• a(n) = Sum_{0<=j<=i<=n} A027144(i, j).at n=10A027153
• Number of increasing mobiles with n elements.at n=8A029768
• Primes p such that the decimal digits of p^2 can be partitioned into two or more nonzero squares.at n=37A048646
• Safe primes (A005385) (p and (p-1)/2 are primes) such that 12*p+1 is also prime.at n=48A075707
• Primes associated with groups in A076077.at n=31A076076
• Primes p such that 13 is the largest of all prime factors of the numbers between p and the next prime (cf. A052248).at n=21A080188
• Twin primes associated with A087900.at n=8A087901
• Prime mean of 8 horizontal, vertical and main diagonal sums associated with primes in A094454.at n=25A094455
• Balanced primes of order eleven.at n=9A096703
• Expansion of (1+x)^3/((1+x)^3+x^4).at n=25A099531
• Primes and their indices such that when their respective SOD's are both prime, the SOD of the index is the nextprime of the prime SOD.at n=32A117458
• Primes p such that (p + nextprime + p) and also (p + previousprime + p) are primes.at n=38A125146
• Numbers k such that (3^k + 8^k)/11 is prime.at n=6A128068
• Primes congruent to 14 mod 61.at n=38A142812
• a(1) = 1; thereafter a(n) is always the smallest integer > a(n-1) not leading to a contradiction, such that any five consecutive digits in the sequence sum up to a prime.at n=35A152605
• Primes congruent to 35 mod 73.at n=31A154628
• Depression-type primes with five digits; from left to right digits decrease to and increase from the central digit.at n=4A157083
• Integers of the form 4n+3 for which Sum_{i=1..u} J(i,4n+3) obtains value zero exactly 7 times, when u ranges from 1 to (4n+3). Here J(i,k) is the Jacobi symbol.at n=26A166057
• Primes q (except greater of twin primes) with result 2 under iterations of {r mod (max prime p < r)} starting at r = q.at n=24A175080
• List of 4-tuples of twin primes q, p, p+2 and q+2 such that 2*q<p<p+2<2*(q+2).at n=41A176821