A059842 The next square after a(n)^3 is a(n+1)^2.

1, 2, 3, 6, 15, 59, 454, 9674, 951501, 928140821, 28276184777782, 150359618976700758746, 1843727887745124274995859697327, 2503486403859294888221025578988349446337176495, 125261571430858575370252424686453280425035047529321451018103304969551

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..21

Formula

a(n+1) = min { i | i^2 > a(n)^3 }.

a(n+1) = floor(sqrt(a(n)^3)) + 1. - Robert G. Wilson v, Mar 22 2001

Example

a(4) = 6 has cube 216. The next square is 225 = 15^2. So a(5) = 15.

Maple

a := proc(n) option remember: if n=1 then RETURN(1) fi: if n=2 then RETURN(2) fi: ceil(a(n-1)^((3.)/(3-1))): end: Digits := 200: for n from 1 to 20 do printf(`%a, `, a(n)) od:

Mathematica

f[n_Integer] := Floor[ N[ Sqrt[n^3] ] ] + 1; NestList[f, 1, 15]

Prog

(PARI) { a=0; for (n=1, 21, write("b059842.txt", n, " ", a=sqrtint(a^3) + 1); ) } \\ Harry J. Smith, Jun 29 2009

Crossrefs

Sequence in context: A320963 A061059 A060796 * A001529 A363505 A069354

Adjacent sequences: A059839 A059840 A059841 * A059843 A059844 A059845

Keyword

nonn

Author

Rainer Rosenthal, Feb 26 2001

Extensions

More terms from James Sellers, Mar 15 2001

Status

approved