A328497 - OEIS

A328497

Terms of A082180 that are not squares or cubes of primes.

418, 27173, 2001341, 16024189487

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OFFSET

1,1

COMMENTS

Complement of A168363 in A082180.

Are there any other terms like 418 that are not in A228562?

No other terms below 2*10^10. - Max Alekseyev, Dec 15 2023

LINKS

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

MATHEMATICA

Select[Range[30000], CompositeQ[#] && Not[IntegerQ[Sqrt[#]]] && Not[IntegerQ[#^(1/3)]] && Mod[Binomial[2*#, #], #] == 2 &] (* Vaclav Kotesovec, Oct 17 2019 *)

PROG

(PARI) forcomposite(c=1, , if(!setintersect(Set(isprimepower(c)), [2, 3]), if(Mod(binomial(2*c, c), c)==2, print1(c, ", "))))

CROSSREFS

The odd terms form A228562.

Cf. A082180, A168363.

Sequence in context: A224557 A080467 A292422 * A138062 A350781 A097233

Adjacent sequences: A328494 A328495 A328496 * A328498 A328499 A328500

KEYWORD

nonn,hard,more

AUTHOR

Felix Fröhlich, Oct 17 2019

EXTENSIONS

a(4) from Max Alekseyev, Dec 15 2023

STATUS

approved