21979

Appears in sequences

• a(n) = n OR n^3 (applied to ternary expansions).at n=27A008469
• Numbers k such that 271*2^k-1 is prime.at n=10A050894
• a(n) is the n-th new record value in A073300.at n=32A073301
• 2*a(n)^2 + 7 is a square.at n=11A077442
• a(0) = -1, a(1) = 2; a(n) = 2*a(n-1) + a(n-2).at n=12A078343
• a(n) = n * prime(prime(n)).at n=30A080697
• Start with the sequence S(0)={1,1} and for k>0 define S(k) to be I(S(k-1)) where I denotes the operation of inserting, for i=1,2,3..., the term a(i)+a(i+1) between any two terms for which 4a(i+1)<=5a(i). The listed terms are the initial terms of the limit of this process as k goes to infinity.at n=22A082981
• Numbers which are the sum of two positive cubes and divisible by 31.at n=34A102658
• Semiprimes in A054567.at n=22A113692
• Fixed-k dispersion for Q = 8: Square array D(g,h) (g, h >= 1), read by ascending antidiagonals.at n=33A120861
• Terms of A024670 that are not in A141805.at n=26A141806
• a(n) = 16*n^2 + 2*n + 1.at n=37A204675
• Part of the y solutions of the Pell equation x^2 - 2*y^2 = +7.at n=5A253811
• a(n) = (2n-2)^3 + (2n-2) - 1.at n=14A255877
• a(n) = 2*a(n - 2) + a(n - 4) with a(0) = a(1) = 2, a(2) = 1, a(3) = 3.at n=23A266504
• a(n) = 2*a(n-4) + a(n-8) for n >= 8.at n=46A266506
• G.f. satisfies: A(x - A(x) + A(x)^2) = x^3.at n=11A291613
• Partial sums of A008137.at n=34A299276