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A358417
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Indices of the triangular numbers in A189475.
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0
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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
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OFFSET
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1,2
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LINKS
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FORMULA
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PROG
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(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
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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