Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
The OEIS is supported by the many generous donors to the OEIS Foundation.
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A358417
Indices of the triangular numbers in A189475.
0
1, 2, 6, 18, 54, 29, 182, 546, 1638, 4914, 1407, 1599, 726, 581, 945, 16362, 1536, 49278, 2175, 7077, 22238, 4224, 6266, 10632, 21440, 38454, 21189, 12801, 219138, 47039, 37494, 119837, 19158, 760898, 182840, 7649, 536847, 75405, 544775, 160520, 365439, 307943
(list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Table of n, a(n) for n=1..42.
FORMULA
A000217(a(n)) = A189475(n).
PROG
(Python)
from itertools import islice, count
from sympy import integer_nthroot
def A358417_gen(): # generator of terms
a = 0
for n in count(1):
c, d = integer_nthroot(((b:=n**2)-a<<3)+1, 2)
if d:
yield c-1>>1
a = b
A358417_list = list(islice(A358417_gen(), 44))
CROSSREFS
Cf. A000217, A036449, A189475, A358416.
Sequence in context: A094864 A120010 A132790 * A372899 A214799 A072850
Adjacent sequences: A358414 A358415 A358416 * A358418 A358419 A358420
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Nov 14 2022
STATUS
approved

Lookup Welcome Wiki Register Music Plot 2 Demos Index WebCam Contribute Format Style Sheet Transforms Superseeker Recents
The OEIS Community
Maintained by The OEIS Foundation Inc.
Last modified September 28 16:16 EDT 2024. Contains 376297 sequences.
License Agreements, Terms of Use, Privacy Policy