21617

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has period 55.at n=28A020394
• Numbers k that divide the (left) concatenation of all numbers <= k written in base 25 (most significant digit on left).at n=19A029494
• Number of partitions satisfying 0 < cn(0,5) + cn(1,5) + cn(4,5) + cn(2,5) and 0 < cn(0,5) + cn(1,5) + cn(4,5) + cn(3,5).at n=37A039904
• Smaller of two consecutive primes whose sum is a square.at n=15A061275
• Primes for which the five closest primes are smaller.at n=10A075037
• Primes which are the sum of three positive 4th powers.at n=32A085318
• Lesser of consecutive primes whose sum is a perfect power (A001597).at n=20A091624
• Primes p such that q-p = 30, where q is the next prime after p.at n=25A124596
• Prime numbers that are the sum of three distinct positive fourth powers.at n=20A126657
• Primes of the form n^2+8.at n=15A138338
• Primes congruent to 23 mod 61.at n=39A142821
• 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), (0, -1, 1), (0, 1, 0), (1, 0, -1)}.at n=11A148093
• Primes of the form 6*n^2+17.at n=40A151953
• Primes in toothpick sequence A153006.at n=26A153009
• Primes of the form (p^2-2)/7, where p is also a prime number.at n=11A165668
• Primes that are the average of the members of emirp pairs.at n=11A178581
• Nonpalindromic primes that are the average of the members of emirp pairs.at n=3A178585
• Primes which are the sum of two numbers of the form k*(k+1)^2/2.at n=42A210646
• Primes p=prime(i) of level (1,6), i.e., such that A118534(i) = prime(i-6).at n=1A216180
• Primes whose base-7 representation also is the base-3 representation of a prime.at n=24A235470