A076442 Odd-digit perfect powers.

1, 9, 1331, 3375, 35937, 59319, 357911, 753571, 759375, 5177717, 5359375, 5735339, 9393931, 17373979, 37595375, 39135393, 37159393753, 99317171591, 175333911173, 397551775977, 1913551573375, 9735913353977, 11997979755957, 17171515157399, 335571975137771

Offset: 1

Author

Robert G. Wilson v and Zak Seidov, Oct 11 2002

Keywords

• nonn
• base

Comments

a(19) > 1.3*10^11. - Robert G. Wilson v, Dec 17 2002

Links

• Giovanni Resta, Table of n, a(n) for n = 1..566 (terms < 10^57)

Crossrefs

Cf. A001597, A014261, A075787.

Programs

Mathematica

NextOddNbr[n_] := Block[{d = If[ EvenQ[n], IntegerDigits[n + 1], IntegerDigits[n + 2]], l}, l = Length[d]; While[l != 1, If[ EvenQ[ d[[l]]], d[[l]]++ ]; If[d[[l]] > 9, d[[l - 1]]++; d[[l]] = 1]; l-- ]; If[ EvenQ[ d[[1]]], d[[1]]++ ]; If[ d[[1]] > 9, d[[1]] = 11]; FromDigits[d]] k = 1; Do[ If[ !PrimeQ[k] && Apply[GCD, Last[ Transpose[ FactorInteger[k]]]] > 1, Print[k]]; k = NextOddNbr[k], {n, 1, 10^8}]

Extensions

Extended by Robert G. Wilson v, Dec 17 2002

Terms a(19) and beyond from Giovanni Resta, Mar 13 2020