login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A216442 Numbers of the form 2^i + 3^j + 5^k, where i, j, k >= 0. 1

%I #44 Oct 28 2022 07:16:13

%S 3,4,5,6,7,8,9,10,11,12,14,15,16,18,20,22,24,26,27,28,29,30,32,33,34,

%T 35,36,38,40,42,44,46,48,50,53,54,56,58,60,64,66,68,70,72,74,78,83,84,

%U 86,87,88,90,92,94,96,98,102,107,108,110,114,116,118,122,127

%N Numbers of the form 2^i + 3^j + 5^k, where i, j, k >= 0.

%C Conjecture: Unlike A004050, which has a limited set of integers expressible in more than one way, this set has no such limit.

%C Number of terms less than or equal to 10^k, k > 0: 8, 56, 238, 615, 1304, 2169, 3606, 5280, 7196, 10414, ....

%H T. D. Noe, <a href="/A216442/b216442.txt">Table of n, a(n) for n = 1..10000</a>

%H Diego Marques and Alain Togbé, <a href="https://doi.org/10.3792/pjaa.89.47">Fibonacci and Lucas numbers of the form 2^a + 3^b + 5^c</a>, Proc. Japan Acad. Ser. A Math. Sci. 89(3): 47-50 (March 2013).

%F There are O(log^3 x) terms of the sequence up to x. - _Charles R Greathouse IV_, Oct 28 2022

%t mx = 140; Union@ Flatten@ Table[2^i + 3^j + 5^k, {i, 0, Log[2, mx]}, {j, 0, Log[3, mx - 2^i]}, {k, 0, Log[5, mx - 2^i - 3^j]}]

%Y Cf. A004050.

%K nonn

%O 1,1

%A _Robert G. Wilson v_, Sep 20 2012

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 19 09:23 EDT 2024. Contains 371782 sequences. (Running on oeis4.)