21083

Appears in sequences

• a(n) = Sum{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; initial terms are 2,3,3.at n=16A049875
• Number of 9-almost primes 9ap such that 2^n < 9ap <= 2^(n+1).at n=21A120040
• Numbers whose square starts with 4 identical digits.at n=22A132391
• Triangle T(n,k) = 3*binomial(n, k)^2 - binomial(n, k) - 1, read by rows.at n=48A144404
• Triangle T(n,k) = 3*binomial(n, k)^2 - binomial(n, k) - 1, read by rows.at n=51A144404
• 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, 1, 0), (0, 0, -1), (0, 0, 1), (1, 0, 1)}.at n=8A150336
• a(n) = 25*n^2 + 2*n.at n=28A154377
• Positive numbers y such that y^2 is of the form x^2+(x+727)^2 with integer x.at n=7A159893
• Number of partitions of n containing a clique of size 9.at n=45A183566
• a(n) = 12*n^2 - 2*n - 1.at n=42A185918
• Number of n X 2 1..5 arrays with every element value z a city block distance of exactly z from another element value z.at n=5A209021
• T(n,k)=Number of nXk 1..5 arrays with every element value z a city block distance of exactly z from another element value z.at n=22A209023
• T(n,k)=Number of nXk 1..5 arrays with every element value z a city block distance of exactly z from another element value z.at n=26A209023
• Numbers m such that (4^m + 23) / 3 is prime.at n=21A261579
• MM-numbers of crossing set partitions.at n=23A324324
• Numbers whose square starts with exactly 4 identical digits.at n=21A346940
• a(n) = Sum_{j=1..n} Sum_{k=1..n} phi(j*k) / phi(k).at n=37A372636
• Consecutive states of the linear congruential pseudo-random number generator 20403*s mod 2^15 when started at s=1.at n=39A384196