18873

Appears in sequences

• Numbers k such that k and k+1 have same sum of divisors.at n=10A002961
• Number of Twopins positions.at n=21A005685
• Numbers k such that k and k+1 have the same sum but an unequal number of divisors.at n=6A054007
• a(n) = floor(product_{k=2..n} log(k)).at n=14A056690
• Numbers k such that sigma(k) divides sigma(k+1), where sigma(k) is sum of positive divisors of k.at n=22A058072
• Numbers k such that sigma(k+1) divides sigma(k), where sigma(k) is the sum of positive divisors of k.at n=26A058073
• Numbers k such that sigma(k)*omega(k) = sigma(k+1)*omega(k+1), where omega(k) is the number of distinct prime divisors of n (A001221).at n=6A063071
• Numbers k such that gcd(sigma(k), sigma(k+1)) > k.at n=37A066025
• Numbers k such that phi(k) divides sigma(k+1) - sigma(k).at n=44A072611
• Numbers n such that abs(d(n) - log(n) + 1 - 2*gamma) is a decreasing sequence, where d(n) is the number of divisors A000005(n) and gamma is Euler's constant A001620.at n=14A089044
• Number of (n+1)X3 0..2 arrays with every 2X2 subblock determinant equal to some horizontal or vertical neighbor 2X2 subblock determinant.at n=2A186212
• Number of (n+1)X4 0..2 arrays with every 2X2 subblock determinant equal to some horizontal or vertical neighbor 2X2 subblock determinant.at n=1A186213
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock determinant equal to some horizontal or vertical neighbor 2X2 subblock determinant.at n=7A186218
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock determinant equal to some horizontal or vertical neighbor 2X2 subblock determinant.at n=8A186218
• Numbers n such that sigma(n+1) - sigma(n) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).at n=18A223136
• Table of consecutive numbers with the same sum of divisors.at n=20A225757
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 155", based on the 5-celled von Neumann neighborhood.at n=30A270327
• Number of nX3 0..1 arrays with every element unequal to 0, 1, 3, 5 or 6 king-move adjacent elements, with upper left element zero.at n=12A304664
• Numbers k in A228058 such that also A001065(k) is in A228058.at n=24A325380
• Numbers m such that the delta(m) = abs(sigma(m+1)/(m+1) - sigma(m)/(m)) is smaller than delta(k) for all k < m.at n=17A335071