A306119 Largest k such that 9^k has exactly n digits 0 (in base 10), conjectured.

34, 36, 68, 56, 65, 106, 144, 134, 119, 138, 154, 186, 194, 191, 219, 208, 247, 267, 199, 314, 292, 263, 319, 303, 307, 345, 431, 401, 375, 388, 413, 498, 488, 504, 465, 513, 565, 464, 481, 541, 568, 532, 588, 542, 600, 677, 649, 633, 613, 734, 627

Offset

0,1

Comments

a(0) is the largest term in A030705: exponents of powers of 9 without digit 0 in base 10.

There is no proof for any of the terms, just as for any term of A020665 and many similar / related sequences. However, the search has been pushed to many magnitudes beyond the largest known term, and the probability of any of the terms being wrong is extremely small, cf., e.g., the Khovanova link.

Links

Table of n, a(n) for n=0..50.

M. F. Hasler, Zeroless powers, OEIS Wiki, March 2014, updated 2018.

T. Khovanova, The 86-conjecture, Tanya Khovanova's Math Blog, Feb. 2011.

W. Schneider, No Zeros, 2000, updated 2003. (On web.archive.org--see A007496 for a cached copy.)

Prog

(PARI) A306119_vec(nMax, M=99*nMax+199, x=9, a=vector(nMax+=2))={for(k=0, M, a[min(1+#select(d->!d, digits(x^k)), nMax)]=k); a[^-1]}

Crossrefs

Cf. A063626: least k such that 9^k has n digits 0 in base 10.

Cf. A305939: number of k's such that 9^k has n digits 0.

Cf. A305929: row n lists exponents of 9^k with n digits 0.

Cf. A030705: { k | 9^k has no digit 0 } : row 0 of the above.

Cf. A020665: largest k such that n^k has no digit 0 in base 10.

Cf. A071531: least k such that n^k contains a digit 0 in base 10.

Cf. A103663: least x such that x^n has no digit 0 in base 10.

Cf. A306112, ..., A306118: analog for 2^k, ..., 8^k.

Sequence in context: A045561 A294282 A067190 * A218006 A345510 A300155

Adjacent sequences: A306116 A306117 A306118 * A306120 A306121 A306122

Keyword

nonn,base

Author

M. F. Hasler, Jun 22 2018

Extensions

Data corrected thanks to a remark by R. J. Mathar, by M. F. Hasler, Feb 11 2023

Status

approved