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A109720 Periodic sequence {0,1,1,1,1,1,1} or n^6 mod 7. +0
15
0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1 (list; graph; listen)
OFFSET

0,1

COMMENT

this sequence also represents n^12 mod 7; n^18 mod 7; (exponents are = 0 mod 6)

Characteristic sequence for numbers n>=1 to be relatively prime to 7. [From Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Oct 29 2008]

Contribution from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 30 2009: (Start)

a(n)=1-A082784(n); a(A047304(n))=1; a(A008589(n))=0;

A033439(n) = SUM(a(k)*(n-k): 0<=k<=n). (End)

LINKS

Index entries for characteristic functions [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 30 2009]

FORMULA

a(n) = 0 if n=0 mod 7; a(n)= 1 else G.f. = (x+x^2+x^3+x^4+x^5+x^6)/(1-x^7)

a(n)=(1/49)*{9*(n mod 7)+2*[(n+1) mod 7]+2*[(n+2) mod 7]+2*[(n+3) mod 7]+2*[(n+4) mod 7]+2*[(n+5) mod 7]-5*[(n+6) mod 7]} - Paolo P. Lava (ppl(AT)spl.at), Nov 21 2006

Multiplicative with a(p) = (if p=7 then 0 else 1), p prime. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 30 2009]

PROGRAM

(Other) sage: [power_mod(n, 6, 7)for n in xrange(0, 105)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 06 2009]

CROSSREFS

Cf. A010876 = n mod 7; A053879 = n^2 mod 7; A070472 = m^3 mod 7; A070512 = n^4 mod 7; A070593 = n^5 mod 7.

Sequence in context: A075897 A135947 A101040 this_sequence A022932 A079421 A164980

Adjacent sequences: A109717 A109718 A109719 this_sequence A109721 A109722 A109723

Cf. A168185, A145568, A168184, A168182, A168181, A097325, A011558, A166486, A011655, A000035. [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 30 2009]

KEYWORD

easy,nonn,new

AUTHOR

Bruce Corrigan (scentman(AT)myfamily.com), Aug 09 2005

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Last modified December 13 23:45 EST 2009. Contains 170824 sequences.


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