A195908 Powers of 7 which have no zero in their decimal expansion.

1, 7, 49, 343, 117649, 823543, 282475249, 1977326743, 11398895185373143, 378818692265664781682717625943

Offset

1,2

Comments

Probably finite. Is 378818692265664781682717625943 the largest term?

No further terms up to 7^50,000, a number with 42,255 digits. - Harvey P. Dale, Jul 14 2022

Links

Table of n, a(n) for n=1..10.

M. F. Hasler, Zeroless powers, OEIS Wiki, Mar 07 2014

C. Rivera, Puzzle 607. A zeroless Prime power, on primepuzzles.net, Sept. 24, 2011.

W. Schneider, NoZeros: Powers n^k without Digit Zero (local copy of www.wschnei.de/digit-related-numbers/nozeros.html), as of Jan 30 2003.

Formula

a(n) = 7^A030703(n).

A000420 intersect A052382.

Mathematica

Select[7^Range[0, 50], DigitCount[#, 10, 0]==0&] (* Harvey P. Dale, Jul 14 2022 *)

Prog

(PARI) for( n=1, 9999, is_A052382(7^n) && print1(7^n, ", "))
(Magma) [7^n: n in [0..3*10^4] | not 0 in Intseq(7^n)]; // Bruno Berselli, Sep 26 2011

Crossrefs

Cf. A195942, A195943, A195944, A195945, A195946, A195948, A007377, A008839, A030700, A030701, A030702, A030703, A030704, A030705, A030706.

Sequence in context: A000420 A373283 A050737 * A033143 A024582 A024587

Adjacent sequences: A195905 A195906 A195907 * A195909 A195910 A195911

Keyword

nonn,base

Author

M. F. Hasler, Sep 25 2011

Extensions

Keyword:fini removed by Jianing Song, Jan 28 2023 as finiteness is only conjectured.

Status

approved