19045

Appears in sequences

• Numbers k such that k, k+1, k+2 and k+3 have the same number of divisors.at n=22A006601
• a(n) = [ 2nd elementary symmetric function of {sqrt(k)} ], k = 1,2,...,n.at n=42A025193
• Average of squares of successive primes: a(n) = (prime(n+1)^2 + prime(n)^2)/2, with n >= 2.at n=31A075892
• Floor(average of first n Fibonacci numbers).at n=26A078620
• a(n) = 529*n + 1.at n=35A158368
• a(n) = 36*n^2 + 1.at n=23A158591
• a(n) = (2*n^3 + 5*n^2 - 17*n)/2.at n=25A162259
• Total area of the shadows of the three views of the version "Tree" of the shell model of partitions with n shells.at n=24A210979
• Numbers k such that distances from k to three nearest squares are three triangular numbers.at n=21A232501
• a(n) = 9*n^2 + 1.at n=46A247792
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 577", based on the 5-celled von Neumann neighborhood.at n=27A273024
• p-INVERT of the positive integers, where p(S) = 1 - 5*S^2.at n=7A290909
• Numbers of the form m^2 + 1 that can be expressed in more than one way as j^2 + k^2 with j > k > 1.at n=24A299708
• Numbers of the form m^2 + 1 that can be expressed in more than one way as j^2 + k^2 with j > k > 1 and gcd(j,k) = 1.at n=11A300166
• A self-"read and extend" sequence built following the rules visible in the Comments section (a kind of Collatz-by-digits sequence).at n=16A316764
• Number of weakly unimodal compositions of n in which the greatest part occurs exactly seven times.at n=55A320318
• Numbers of the form p*q*r where p, q, r are distinct primes congruent to 1 mod 4 such that Legendre(p/q) = Legendre(p/r) = Legendre(q/r) = -1.at n=15A323271
• Let p(n) be the n-th composite squarefree number. a(n) is the smallest integer q that forms a pure idempotent product.at n=24A325945