18543

Appears in sequences

• Numbers k such that 193*2^k-1 is prime.at n=10A050848
• Split positive integers into extending even groups and sum: 1+2, 3+4+5+6, 7+8+9+10+11+12, 13+14+15+16+17+18+19+20, ...at n=21A061317
• Numbers such that the sum of the factorials of the digits of the fourth power is a square.at n=28A126077
• Numbers k such that k^3 divides 5^(k^2) + 1.at n=8A128679
• Numbers k such that k^3 divides 4^(k^2) - 1.at n=12A129212
• Numbers k such that gpf(k^2+1)/k sets a new record of low value, where gpf(k) is the greatest prime dividing k (A006530).at n=22A173561
• Numbers k such that k^3 divides 20^(k^2) + 1.at n=11A177820
• a(n) is the smallest number such that a(n)^2 + 1 is divisible by A002144(1)* A002144(2)*...* A002144(n).at n=4A181413
• Largest number k such that the greatest prime factor of k^2+1 is A002313(n), the n-th prime not congruent to 3 mod 4.at n=5A185389
• Irregular triangle of numbers k such that A002313(n), the n-th prime not congruent to 3 mod 4, is the largest prime factor of k^2 + 1.at n=31A223702
• Number of partitions of n such that if the length is k then k is not a part.at n=37A229816
• Row sums of the triangular array A246694.at n=41A246695
• Numbers n such that n^2 + 1 can be expressed as j^2 + k^2, j > k > 1, in more ways than for any smaller n.at n=11A300161
• a(n) = greatest integer N such that (number of primes <= N) >= (number of numbers <= N that contain a zero in base n).at n=19A306526
• Sum of the next n positive integers repeated (A008619).at n=41A319006
• Number of isomorphism classes of virtual racks of order n.at n=7A385040