login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A225017 Odd part of digit sum of 5^n divided by maximal possible power of 5. 9
1, 1, 7, 1, 13, 11, 19, 23, 1, 13, 1, 19, 7, 23, 17, 11, 29, 7, 1, 59, 61, 31, 67, 37, 41, 77, 79, 89, 17, 83, 91, 13, 53, 89, 103, 23, 109, 13, 31, 67, 13, 137, 29, 149, 151, 29, 7, 1, 29, 79, 151, 19, 13, 119, 127, 167, 49, 43, 211, 191, 199, 97, 187, 17, 83 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Does the sequence contain every prime greater than 5?

LINKS

Peter J. C. Moses and Alois P. Heinz, Table of n, a(n) for n = 0..10000 (terms n = 0..999 from Peter J. C. Moses)

FORMULA

a(n) = A132740(A055566(n)). - Michel Marcus, Dec 10 2018

MAPLE

a:= proc(n) local m, r; m, r:= 0, 5^n;

      while r>0 do m:= m+irem(r, 10, 'r') od;

      while irem(m, 2, 'r')=0 do m:=r od;

      while irem(m, 5, 'r')=0 do m:=r od; m

    end:

seq(a(n), n=0..80);  # Alois P. Heinz, Apr 24 2013

MATHEMATICA

Map[#/(2^IntegerExponent[#, 2] 5^IntegerExponent[#, 5])&[Total[ IntegerDigits[5^#]]]&, Range[0, 99]] (* Peter J. C. Moses, Apr 24 2013 *)

PROG

(PARI) a(n) = my(x = sumdigits(5^n)); x/5^valuation(x, 5) >> valuation(x, 2); \\ Michel Marcus, Dec 10 2018

CROSSREFS

Cf. A055566, A132740.

Sequence in context: A060393 A060394 A203810 * A268919 A040055 A317016

Adjacent sequences:  A225014 A225015 A225016 * A225018 A225019 A225020

KEYWORD

nonn,base

AUTHOR

Vladimir Shevelev, Apr 24 2013

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 15 20:00 EDT 2019. Contains 325056 sequences. (Running on oeis4.)