A122842 - OEIS

A122842

Square roots of the odd indexed terms of A038547.

1, 3, 9, 27, 15, 243, 729, 45, 6561, 19683, 135, 177147, 225, 105, 4782969, 14348907, 1215, 675, 387420489, 3645, 3486784401, 10460353203, 315, 94143178827, 3375, 32805, 2541865828329, 6075, 98415, 68630377364883

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OFFSET

1,2

COMMENTS

A038547(n) is the least number with exactly n odd divisors. For odd n these are perfect squares.

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = sqrt(A038547(2*n-1)).

a(n) = sqrt(A119265(2*n-1, 2*n-1)).

a(n) = 3^(n-1) for n = (p+1)/2, where p is an odd prime.

a(3*n+2) = 5*3^n for n = (p-1)/2, where p is an odd prime.

EXAMPLE

a(1) = 1 because A038547(1) = 1.

a(2) = 3 because A038547(3) = 9.

a(5) = 15 because A038547(9) = 225.

MATHEMATICA

(* Function a038547[ ] is defined in A038547 *)

a122842[n_]:=Sqrt[a038547[2n-1]]

Map[a122842, Range[30]] (* Hartmut F. W. Hoft, Feb 07 2023 *)

CROSSREFS

Cf. A038547, A121858, A001227, A005179, A119265.

Cf. A007051, A070826, A002110.

Sequence in context: A070359 A271015 A131997 * A070358 A321542 A321540

Adjacent sequences: A122839 A122840 A122841 * A122843 A122844 A122845

KEYWORD

nonn

AUTHOR

Alexander Adamchuk, Sep 13 2006, Sep 25 2006

EXTENSIONS

More terms from R. J. Mathar, Sep 20 2006

Edited by Hartmut F. W. Hoft, Feb 07 2023

STATUS

approved