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

1,2

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)

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}]

Crossrefs

Cf. A001597, A014261, A075787.

Sequence in context: A276823 A020261 A266864 * A076704 A117053 A270067

Adjacent sequences: A076439 A076440 A076441 * A076443 A076444 A076445

Keyword

nonn,base

Author

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

Extensions

Extended by Robert G. Wilson v, Dec 17 2002

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

Status

approved