login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A333965 Numbers k such that k * A171744(k) increases to a record. 0
1, 2, 5, 6, 8, 12, 14, 16, 18, 20, 25, 27, 32, 43, 45, 46, 52, 58, 70, 71, 77, 81, 91, 105, 109, 149, 158, 176, 240, 247, 297, 303, 401, 421, 431, 531, 536, 542, 543, 608, 617, 622, 640, 643, 667, 677, 685, 713, 720, 748, 751, 1028, 1085, 1203, 1282, 1320, 1466, 1600 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This sequence shows where A171744(k) is larger than usual around k.

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

6 is in the sequence as A171744(6) = 22 and 6*22 = 132. This is a record; no n less than 6 produces a product of at least 132.

MATHEMATICA

With[{s = Array[Block[{p = Prime@ #, k = 1}, While[Min@ DigitCount[p^k] == 0, k++]; k #] &, 1600]}, Map[FirstPosition[s, #][[1]] &, Union@ FoldList[Max, s]]] (* Michael De Vlieger, Aug 21 2020 *)

PROG

(PARI) f(n) = {my(k=1, p=prime(n)); while(#Set(digits(p^k))<10, k++); k; } \\ A171744

lista(nn) = {my(m=0, x); for (n=1, nn, x = n*f(n); if (x >m, m = x; print1(n, ", ")); ); } \\ Michel Marcus, Jan 26 2021

CROSSREFS

Cf. A171744.

Sequence in context: A230902 A243680 A280381 * A105107 A002253 A032716

Adjacent sequences: A333962 A333963 A333964 * A333966 A333967 A333968

KEYWORD

nonn,base

AUTHOR

David A. Corneth, Aug 14 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 30 12:01 EST 2023. Contains 359943 sequences. (Running on oeis4.)