26561

Properties

Appears in sequences

• One half of number of non-self-conjugate partitions; also half of number of asymmetric Ferrers graphs with n nodes.at n=42A000701
• Numbers k such that the continued fraction for sqrt(k) has period 83.at n=24A020422
• Number of partitions of n into an odd number of parts.at n=42A027193
• Primes of the form k^2 - 8.at n=37A028886
• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 10.at n=35A031423
• Largest prime below prime(n)^2 (A001248).at n=37A054270
• Primes p such that x^48 = 2 has no solution mod p, but x^24 = 2 has a solution mod p.at n=32A059669
• Irregular primes with irregularity index three.at n=36A060975
• Primes formed from a concatenation of 2 and 3^k for some k.at n=6A068714
• Primes that can be formed by concatenating 2^a and 3^b.at n=32A068801
• Primes which are the sum of three positive 4th powers.at n=35A085318
• If p(x) is the x-th prime, then the n-th set of 4 consecutive sexy prime pairs starts at p(a(n)).at n=31A095963
• Primes p of the form a^4+b^4+c^4 with a,b,c>=1 such that a^2+b^2+c^2 is another prime < p.at n=27A126117
• a(n) = Sum_{m=1..n} gcd(s(n,m), S(n,m)), where s(n,m) is an unsigned Stirling number of the first kind and S(n,m) is a Stirling number of the second kind.at n=12A128266
• Expansion of phi(-q^3) / f(-q)^2 in powers of q where phi(), f() are Ramanujan theta functions.at n=24A137685
• Smallest primes p = p(k) with (p(k)+p(k+1)+p(k+2))/15 an integer.at n=21A168556
• a(n) = smallest prime > a(n-1) such that a(n)+a(n-1) is multiple of k, a(1)=2, k=101.at n=37A178468
• Sequence of primes separated by [sequence of prime] elements. 2, [find 2nd prime after 2 = ] 5, [find 3rd prime after 5 =] 13, [find 5th prime after 13 =] 61, ..., etc.at n=39A180302
• Primes p with property that there exists a number d>0 such that numbers p-k*d, k=1...7, are seven primes.at n=38A216590
• Number of (n+3) X 4 0..2 matrices with each 4 X 4 subblock idempotent.at n=9A224721