27074

Appears in sequences

• a(n) = Sum_{i=1..floor((n+1)/4)} a(2*i-1) * a(n-2*i+1), with a(1)=a(2)=1 and a(3)=2.at n=20A024723
• 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, 0, 0), (1, -1, 0), (1, 0, -1), (1, 1, 1)}.at n=9A149427
• Number of partitions of n such that the number of parts and the greatest part are coprime.at n=40A200750
• Numbers n for which number of iterations to reach the largest equals number of iterations to reach 1 from the largest in Collatz (3x+1) trajectory of n.at n=26A224303
• a(n) is the number of terms in the expansion of (x-y)*(x^4-y^4)*(x^9-y^9)*...*(x^(n^2)-y^(n^2)).at n=42A225549
• Number T(n,k) of equivalence classes of ways of placing k 5 X 5 tiles in an n X n square under all symmetry operations of the square; irregular triangle T(n,k), n>=5, 0<=k<=floor(n/5)^2, read by rows.at n=39A236800
• p-INVERT of (1,1,0,0,0,0,...), where p(S) = 1 - 2 S^2 - S^4.at n=13A291403