A358416 a(1) = 0 and a(n+1) > a(n) is the smallest integer such that a(n+1)^2-a(n)^2 is triangular.

0, 1, 2, 5, 14, 41, 46, 137, 410, 1229, 3686, 3818, 3982, 4015, 4036, 4091, 12272, 12320, 36959, 36991, 37328, 40505, 40615, 40856, 41542, 44222, 51913, 54032, 54785, 164354, 167686, 169769, 189742, 190225, 570674, 585136, 585161, 697507, 699542, 798592, 806618

Offset

1,3

Comments

Square roots of A036449.

Links

Table of n, a(n) for n=1..41.

Formula

a(n) = sqrt(A036449(n)).

Prog

(Python)
from itertools import count, islice
from sympy import integer_nthroot
def A358416_gen(): # generator of terms
    yield (a:=0)
    for n in count(1):
        if integer_nthroot(((b:=n**2)-a<<3)+1, 2)[1]:
            yield n
            a = b
A358416_list = list(islice(A358416_gen(), 41))

Crossrefs

Cf. A036449.

Sequence in context: A159308 A163189 A243881 * A225691 A116846 A080558

Adjacent sequences: A358413 A358414 A358415 * A358417 A358418 A358419

Keyword

nonn

Author

Chai Wah Wu, Nov 14 2022

Status

approved