21825

Appears in sequences

• a(n) = ceiling(n*phi^15), where phi is the golden ratio, A001622.at n=16A004970
• a(n) = a(n-1)+a(n-4).at n=30A014097
• From Renyi's "beta expansion of 1 in base 3/2": sequence gives a(1), a(2), ... where x(n) = a(n)/2^n, with 0 < a(n) < 2^n, a(1) = 1, a(n) = 3*a(n-1) modulo 2^n.at n=18A058842
• Numbers k for which 2*k-1, 4*k-1, 8*k-1 and 16*k-1 are primes.at n=21A124494
• Column 3 of array in A133713.at n=8A133718
• Column 4 of triangle in A133721.at n=36A133723
• Column 5 of triangle in A133721.at n=46A133724
• Column 6 of triangle in A133721.at n=56A133733
• Values of x in solutions (x,y,z) to the Diophantine equation x^3-x^2+y^3-y^2=z^3-z^2, with 1<x<y<z.at n=33A138667
• 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, 0), (-1, 0, 1), (0, 0, -1), (1, 0, -1), (1, 1, 1)}.at n=8A149688
• a(n) = 97*n^2.at n=15A174338
• "Early bird" squares: write the square numbers in a string 149162536496481100... . Sequence gives numbers k such that k^2 occurs in the string ahead of its natural place.at n=38A181585
• Centered 44-gonal numbers.at n=31A195318
• Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 4,4,2,0,1,2,0 for x=0,1,2,3,4,5,6.at n=5A198088
• G.f.: Sum_{n>=0} Product_{k=1..n} ((1+x)^(2*k-1) - 1).at n=6A207569
• Indices of primes in A141523.at n=39A235862
• Number of length n arrays of permutations of 0..n-1 with each element moved by -8 to 8 places and the average of every three consecutive elements is never greater than the median of the previous three elements.at n=15A263734
• Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 324", based on the 5-celled von Neumann neighborhood.at n=15A281105
• Number of nX4 0..1 arrays with every element unequal to 0, 1, 2, 3, 4 or 8 king-move adjacent elements, with upper left element zero.at n=4A316179
• Number of nX5 0..1 arrays with every element unequal to 0, 1, 2, 3, 4 or 8 king-move adjacent elements, with upper left element zero.at n=3A316180