A136360 - OEIS

A136360

Square roots of the perfect squares in A133459.

6, 9, 12, 17, 22, 24, 25, 26, 60, 86, 99, 120, 188, 200, 202, 210, 214, 238, 243, 268, 336, 348, 415, 476, 481, 504, 524, 539, 565, 602, 693, 704, 720, 726, 732, 846, 899, 961, 965, 990, 1026, 1202, 1218, 1221, 1224, 1320, 1551, 1602, 1687, 1716, 1724, 1734

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Corresponding squares in A133459 are listed in A136359(n) = a(n)^2.

Note that some numbers in a(n) are also perfect squares: m = k^2 = {9, 25, 961, 17424, ...}. The corresponding numbers k such that a(n) = k^2 are listed in A136361.

LINKS

Table of n, a(n) for n=1..52.

FORMULA

a(n) = sqrt(A136359(n)).

EXAMPLE

A133459 begins {2, 7, 12, 19, 24, 36, 41, 46, 58, 76, 80, 81, 93, 115, 127, 132, 144, 150, 166, 197, 201, 202, 214, 236, 252, 271, 289, ...}.

Thus a(1) = sqrt(36) = 6, a(2) = sqrt(81) = 9, a(3) = sqrt(144) = 12, a(4) = sqrt(289) = 17 that are the square roots of the perfect squares in A133459.

MATHEMATICA

Sqrt[ Select[ Intersection[ Flatten[ Table[ i^2*(i+1)/2 + j^2*(j+1)/2, {i, 1, 300}, {j, 1, i} ] ] ], IntegerQ[ Sqrt[ # ] ] & ] ]

CROSSREFS

Cf. A136359, A136361, A133459, A002311, A002411, A053721.

Sequence in context: A001474 A084806 A020938 * A023483 A023042 A128245

Adjacent sequences: A136357 A136358 A136359 * A136361 A136362 A136363

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Dec 25 2007

STATUS

approved