28643

Properties

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Fibonacci numbers), t = A014306.at n=40A024467
• Primes arising in A053782.at n=26A053872
• Primes which are the sum of three positive 4th powers.at n=37A085318
• Indices of primes in the sequence defined by A(0) = 41, A(n) = 10*A(n-1) + 21 for n > 0.at n=27A101723
• 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=29A126117
• Prime numbers that are the sum of three distinct positive fourth powers.at n=23A126657
• Primes p such that continued fraction of (1 + sqrt(p))/2 has period 6: primes in A146331.at n=28A146351
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (1, -1, -1), (1, 0, 1), (1, 1, 0)}.at n=8A150378
• Number of -n..n arrays x(0..4) of 5 elements with zero sum and no element more than one greater than the previous.at n=20A199849
• Primes formed by inserting a semiprime between the semiprime's ordered factors.at n=7A229480
• Primes which are sum of the first k composite numbers and such that the sum of the first k+1 composites is also prime.at n=7A234847
• Sum of 4th powers of proper divisors of n.at n=38A279363
• Primes for which the sum of all preceding odd-indexed prime gaps is exactly one greater than the sum of all preceding even-indexed prime gaps.at n=22A282178
• Primes that can be generated by the concatenation in base 6, in descending order, of two consecutive integers read in base 10.at n=17A287307
• Number of connected one-sided arrangements of n pseudo-circles in the affine plane, in the sense that the union of the boundaries of the pseudo-circles is a connected set.at n=5A288565
• Number of compositions of n with weakly increasing differences.at n=35A325546
• Union of 2, A282178, and A330339.at n=30A330554
• Primes p such that p+j, p+k, q+j, q+k are all prime, where q is the next prime after p, j = p mod A007953(q) and k = q mod A007953(p).at n=0A341326
• Primes p such that (p-1)/2, (p-2)/3, 2*p+1, 3*p+2 are all prime numbers.at n=3A348307
• Sum of the 4th powers of the odd proper divisors of n.at n=38A352032