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A036380 Number of true prime powers whose binary order, ceiling[ Log[ 2,p^x ] ], is n. +0
3
0, 1, 1, 2, 3, 2, 4, 3, 4, 6, 5, 9, 10, 11, 17, 15, 26, 31, 39, 53, 68, 90, 125, 159, 216, 290, 391, 536, 719, 971, 1329, 1812, 2477, 3386, 4626, 6351, 8729, 11995, 16459, 22669, 31259, 43049 (list; graph; listen)
OFFSET

1,4

EXAMPLE

The 5 prime-powers between 1025 and 2048 are 1331=11^3, 1369=37^2, 1681=41^2, 1849=43^2 and 2048.

MATHEMATICA

t=Table[Length[Union[Flatten[Table[Table[Prime[w]^s, {w, 1, PrimePi[2^(n/s)]}], {s, 2, g+1}]]] ], {n, 1, 42}] Delete[t-RotateRight[t], 1]

CROSSREFS

Cf. A029837, A036378-A036390.

Sequence in context: A118653 A076753 A068962 this_sequence A139094 A054384 A026400

Adjacent sequences: A036377 A036378 A036379 this_sequence A036381 A036382 A036383

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu)

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Last modified September 7 23:08 EDT 2008. Contains 143486 sequences.


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