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A084067 Integer coefficients of A(x), where 1<=a(n)<=12, such that A(x)^(1/12) consists entirely of integer coefficients. 12
1, 12, 6, 4, 9, 12, 4, 12, 12, 8, 6, 12, 6, 12, 12, 12, 12, 12, 8, 12, 9, 12, 12, 12, 12, 12, 6, 12, 6, 12, 10, 12, 6, 12, 12, 12, 2, 12, 6, 8, 6, 12, 12, 12, 12, 4, 12, 12, 8, 12, 12, 8, 3, 12, 4, 12, 12, 4, 12, 12, 9, 12, 6, 4, 6, 12, 4, 12, 12, 12, 12, 12, 2, 12, 6, 12, 3, 12, 6, 12, 3, 8 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

More generally, the sequence: "integer coefficients of A(x), where 1<=a(n)<=m, such that A(x)^(1/m) consists entirely of integer coefficients", appears to have a unique solution for all m>0. Are these sequences ever periodic?

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 0..3000.

MATHEMATICA

a[0] = 1; a[n_] := a[n] = Block[{k = 1, s = Sum[a[i]*x^i, {i, 0, n-1}]}, While[ Union[ IntegerQ /@ CoefficientList[ Series[(s+k*x^n)^(1/12), {x, 0, n}], x]] != {True}, k++ ]; k]; Table[ a[n], {n, 0, 81}] (* Robert G. Wilson v *)

CROSSREFS

Cf. A083952, A083953, A083954, A083955, A083956, A083947 A083948, A083949, A083950, A084066.

Sequence in context: A033332 A051725 A070292 * A075247 A173853 A040135

Adjacent sequences:  A084064 A084065 A084066 * A084068 A084069 A084070

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), May 10 2003

EXTENSIONS

More terms from Robert G. Wilson v (rgwv(at)rgwv.com), Jul 26 2005

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Last modified February 15 08:06 EST 2012. Contains 205718 sequences.