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URL: https://oeis.org/A256135

⇱ A256135 - OEIS

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A256135
a(n) = 5^A000120(n).
3
1, 5, 5, 25, 5, 25, 25, 125, 5, 25, 25, 125, 25, 125, 125, 625, 5, 25, 25, 125, 25, 125, 125, 625, 25, 125, 125, 625, 125, 625, 625, 3125, 5, 25, 25, 125, 25, 125, 125, 625, 25, 125, 125, 625, 125, 625, 625, 3125, 25, 125, 125, 625, 125, 625, 625, 3125, 125, 625, 625, 3125, 625, 3125, 3125, 15625
OFFSET
0,2
COMMENTS
Also, a row of the square array A256140.
It appears that when A151780 is regarded as a triangle in which the row lengths are the powers of 2, this is what the rows converge to.
FORMULA
a(n) = A000351(A000120(n)). - Michel Marcus, Mar 21 2015
G.f.: Product_{k>=0} (1 + 5*x^(2^k)). - Ilya Gutkovskiy, Feb 28 2017
EXAMPLE
Also, written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
1;
5;
5, 25;
5, 25, 25, 125;
5, 25, 25, 125, 25, 125, 125, 625;
...
MATHEMATICA
5^# & /@ Nest[Join[#, # + 1] &, {0}, 6] (* Michael De Vlieger, Mar 20 2015, after IWABUCHI Yu(u)ki at a000120 *)
PROG
(PARI) a(n) = 5^hammingweight(n); \\ Michel Marcus, Mar 21 2015
KEYWORD
nonn
AUTHOR
Omar E. Pol, Mar 19 2015
EXTENSIONS
More terms from Michael De Vlieger, Mar 20 2015
STATUS
approved