login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A328850 Squares in whose primorial base expansion only even digits appear. 3
0, 4, 16, 64, 144, 196, 484, 900, 1024, 1444, 1764, 2116, 2304, 4624, 5184, 5476, 6084, 6724, 13924, 14400, 14884, 18496, 19044, 20164, 23104, 23716, 24964, 28224, 29584, 61504, 65536, 66564, 70756, 73984, 79524, 80656, 85264, 88804, 90000, 121104, 131044, 135424, 139876, 186624, 195364, 204304, 209764, 242064, 260100, 264196 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Squares in A328849, squares such that also the prime factor form (A276086) of their primorial base expansion is a square,

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..390

Index entries for sequences related to primorial base

FORMULA

a(n) = A000290(A328838(n)).

EXAMPLE

12^2 = 144 is written as "4400" in primorial base (A049345), as 4*A002110(3) + 4*A002110(2) + 0*A002110(1) + 0*A002110(0) = 4*30 + 4*6 = 144, thus its prime code encoding, A276086(144) = prime(4)^4 * prime(3)^4 = 7^4 * 5^4 = 1500625 is also a square, and 144 is included in this sequence.

PROG

(PARI)

A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };

isA328850(n) = (issquare(n) && issquare(A276086(n)));

CROSSREFS

Cf. A328838 (gives the square roots).

Intersection of A000290 and A328849.

Cf. A002110, A010052, A049345, A276086.

Sequence in context: A275217 A158988 A337968 * A330687 A027676 A249567

Adjacent sequences:  A328847 A328848 A328849 * A328851 A328852 A328853

KEYWORD

nonn,base

AUTHOR

Antti Karttunen, Oct 30 2019

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 18 14:50 EDT 2021. Contains 345118 sequences. (Running on oeis4.)