30751

Appears in sequences

• a(n) = n^3 + n^2 - 1.at n=30A003777
• Numerators of continued fraction convergents to sqrt(615).at n=7A042180
• Expansion of (1-x^3)/(1-2x-x^3+x^4).at n=14A052903
• Shallow diagonal of triangular spiral in A051682.at n=41A081275
• Least j > 1 for n > 0 such that j^2 = (n^2 + 1)*(k^2) + (n^2 + 1)*k + 1 where k sequence = A106230.at n=31A106229
• Integers i such that 9*i = 25 X i, but 17*i is not 49 X i.at n=29A115811
• a(n) = 1250*n^2 - 100*n + 1.at n=4A154374
• a(n) = 961*n - 1.at n=31A158412
• a(n) = 32*n^2 - 1.at n=30A158563
• Triangle read by rows: For 1 <= m <= n, t(n,m) = the smallest positive integer that when read in binary contains exactly (n+1-m) runs of 0's and 1's, all runs being of distinct lengths m through n in any order within binary t(n,m).at n=18A161000
• Number of permutations of 1..n with displacements restricted to {-5,-4,-3,-1,0,2}.at n=15A189587
• Small positive integer solutions of the simultaneous equations y = ax + b and y^2 = ax^3 + b.at n=59A262598
• Number T(n,k) of set partitions of [n] where k is minimal such that for each block b the smallest integer interval containing b has at most k elements; triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=64A276727
• Number of set partitions of [n] such that for each block b the smallest integer interval containing b has at most nine elements and for at least one block c the smallest integer interval containing c has exactly nine elements.at n=1A320559
• Numbers of the form (k^2 - 2) / 2 where k - 1 and k + 1 are both odd composite numbers.at n=36A339480
• a(n) = Sum_{1 <= i, j <= n} gcd(i, j, n)^3.at n=30A368743
• Sum of the legs of the unique primitive Pythagorean triple whose inradius is A000032(n) and such that its long leg and its hypotenuse are consecutive natural numbers.at n=10A381721