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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A201920 a(n) = 2^n mod 125. 2
1, 2, 4, 8, 16, 32, 64, 3, 6, 12, 24, 48, 96, 67, 9, 18, 36, 72, 19, 38, 76, 27, 54, 108, 91, 57, 114, 103, 81, 37, 74, 23, 46, 92, 59, 118, 111, 97, 69, 13, 26, 52, 104, 83, 41, 82, 39, 78, 31, 62, 124, 123, 121, 117, 109, 93, 61, 122, 119, 113, 101, 77, 29 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..10000

Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1).

FORMULA

For n > 50: a(n) = a(n-1) - a(n-50) + a(n-51).

G.f.: (1 + x + 2x^2 + 4x^3 + 8x^4 + 16x^5 + 32x^6 - 61x^7 + 3x^8 + 6x^9 + 12x^10 + 24x^11 + 48x^12 - 29x^13 - 58x^14 + 9x^15 + 18x^16 + 36x^17 - 53x^18 + 19x^19 + 38x^20 - 49x^21 + 27x^22 + 54x^23 - 17x^24 - 34x^25 + 57x^26 - 11x^27 - 22x^28 - 44x^29 + 37x^30 - 51x^31 + 23x^32 + 46x^33 - 33x^34 + 59x^35 - 7x^36 - 14x^37 - 28x^38 - 56x^39 + 13x^40 + 26x^41 + 52x^42 - 21x^43 - 42x^44 + 41x^45 - 43x^46 + 39x^47 - 47x^48 + 31x^49 + 63x^50) / ((1-x)*(1+x^2)*(1 - x^2 + x^4 - x^6 + x^8 - x^10 + x^12 - x^14 + x^16 - x^18 + x^20 - x^22 + x^24 - x^26 + x^28 - x^30 + x^32 - x^34 + x^36 - x^38 + x^40 - x^42 + x^44 - x^46 + x^48)).

Periodic with period 100.

EXAMPLE

a(7) = 2^7 mod 125 = 3.

MATHEMATICA

PowerMod[2, Range[0, 100], 125] (* Harvey P. Dale, Aug 12 2013 *)

PROG

(PARI) a(n)=lift(Mod(2, 125)^n) \\ Charles R Greathouse IV, Mar 22 2016

(MAGMA) [Modexp(2, n, 125): n in [0..120]]; // G. C. Greubel, Oct 17 2018

(GAP) a:=List([0..100], n->PowerMod(2, n, 125));; Print(a); # Muniru A Asiru, Jan 27 2019

CROSSREFS

Cf. A070402, A070336.

Sequence in context: A128901 A025489 A160686 * A223700 A036140 A036138

Adjacent sequences:  A201917 A201918 A201919 * A201921 A201922 A201923

KEYWORD

nonn,easy

AUTHOR

Franz Vrabec, Dec 06 2011

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 October 16 01:33 EDT 2019. Contains 328038 sequences. (Running on oeis4.)