21977

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 81.at n=21A020420
• Smallest nontrivial extension of n-th cube which is a prime.at n=12A030692
• Partial sums of A048655.at n=10A048746
• Concatenation of n^3 and 7.at n=12A061679
• Primes of the form 666*k - 1.at n=11A063472
• Let s(k) denote the k-th term of an integer sequence such that s(0)=0 and s(i) for all i>0 is the least natural number such that no four elements of {s(0),..,s(i)} are in arithmetic progression. Then it appears that there are many set of 3 consecutive integers in s(k). Sequence gives the smallest element in those triples.at n=31A071711
• Primes congruent to 17 mod 61.at n=39A142815
• Primes of the form n+(n+3)^3, n>=0.at n=7A162004
• Primes p such that p-1 and p+1 each contain at least one cubed prime in their prime factorization.at n=33A162870
• Primes of the form (2+n)*(1+2*n)+(1+n)*(2+2*n).at n=20A171748
• Primes of the form 13*n^2+3*n+1.at n=20A176783
• Primes of the form 10n^3+7.at n=6A201305
• Number of binary necklaces with n beads and at least three consecutive black beads.at n=18A351360
• Complement of A381767.at n=10A382131
• Prime numbersat n=2462