A338433 Values of n for which A070939(n^3) differs from A004221(n).

1, 20, 40, 80, 101, 126, 127, 159, 160, 161, 200, 201, 202, 203, 252, 253, 254, 255, 317, 318, 319, 320, 321, 322, 399, 400, 401, 402, 403, 404, 405, 406, 502, 503, 504, 505, 506, 507, 508, 509, 510, 511, 631, 632, 633, 634, 635, 636, 637, 638, 639, 640, 641, 642, 643, 644, 645

Offset: 1

Author

Jeremy Gardiner, Oct 27 2020

Keywords

• nonn

Comments

Sequence gives the values of n for which the length of the binary representation of n^3 differs from ceiling(10*log_10(n)) rounded up.

The largest number not in the sequence is 158489319246111348520210137339 = floor(10^29.2). - Robert Israel, Oct 27 2020

Links

• Jeremy Gardiner, Table of n, a(n) for n = 1..1083
• Index entries for linear recurrences with constant coefficients, signature (2,-1).

Crossrefs

Cf. A004221, A070939, A111393, A329193.

Programs

Maple

filter:= n -> evalb(ilog2(n^3)+1 <> ceil(10*log[10](n))):
select(filter, [$1..1000]); # Robert Israel, Oct 27 2020

Mathematica

Select[Range[1000], IntegerLength[#^3, 2] != Ceiling[10*Log10[#]] &] (* Amiram Eldar, Oct 27 2020 *)