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A274591 Least number k such that k-1, k, k+1 are the sum of two nonzero squares in exactly n ways. 0
73, 22049, 90707201, 4359889 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding triples are (72, 73, 74), (22048, 22049, 22050), (90707200, 90707201, 90707202), (4359888, 4359889, 4359890) for first four terms.

a(6) = 1428907401, a(8) = 2305281745. No more terms < 2*10^11. - Lars Blomberg, Jun 01 2018

a(5) > 10^15, if it exists. - Giovanni Resta, Jun 05 2018

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

a(2) = 22049 because 22048 = 12^2 + 148^2 = 68^2 + 132^2, 22049 = 32^2 + 145^2 = 40^2 + 143^2, 22050 = 21^2 + 147^2 = 105^2 + 105^2.

CROSSREFS

Cf. A064716, A274548.

Sequence in context: A210382 A091757 A070531 * A232293 A232366 A183490

Adjacent sequences:  A274588 A274589 A274590 * A274592 A274593 A274594

KEYWORD

nonn,hard,more

AUTHOR

Altug Alkan, Jun 29 2016

STATUS

approved

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Last modified January 22 11:21 EST 2021. Contains 340362 sequences. (Running on oeis4.)