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!)
A354776 Even numbers that are the sum of two squares; also numbers which are twice the sum of two squares. 0
0, 2, 4, 8, 10, 16, 18, 20, 26, 32, 34, 36, 40, 50, 52, 58, 64, 68, 72, 74, 80, 82, 90, 98, 100, 104, 106, 116, 122, 128, 130, 136, 144, 146, 148, 160, 162, 164, 170, 178, 180, 194, 196, 200, 202, 208, 212, 218, 226, 232, 234, 242, 244, 250, 256, 260, 272, 274, 288, 290, 292, 296, 298, 306, 314, 320 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
This is both the even subsequence of A001481, and twice A001481. It is an easy exercise to show that these two definitions produce the same sequence.
LINKS
PROG
(Python)
from itertools import count, islice
from sympy import factorint
def A354776_gen(): # generator of terms
return filter(lambda n:(lambda m:all(d & 3 != 3 or m[d] & 1 == 0 for d in m))(factorint(n//2)), count(0, 2))
A354776_list = list(islice(A354776_gen(), 30)) # Chai Wah Wu, Jun 27 2022
CROSSREFS
Cf. A001481. Essentially the same as A128106.
Sequence in context: A171757 A350780 A128106 * A125021 A085406 A022340
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 26 2022, following a suggestion from Charles Kusniec.
STATUS
approved

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 March 29 08:13 EDT 2024. Contains 371265 sequences. (Running on oeis4.)