A213013 (2^3^4^5^...^n) mod n

0, 2, 0, 2, 2, 1, 0, 8, 2, 2, 8, 5, 8, 2, 0, 2, 8, 18, 12, 8, 2, 16, 8, 2, 18, 26, 8, 11, 2, 2, 0, 2, 2, 22, 8, 31, 18, 5, 32, 2, 8, 27, 24, 17, 16, 8, 32, 43, 2, 2, 44, 45, 26, 2, 8, 56, 40, 47, 32, 33, 2, 8, 0, 57, 2, 5, 36, 62, 22, 60, 8, 1, 68, 2, 56, 57, 44, 8, 32, 80, 2, 2, 8, 2

Offset

2,2

Comments

a(n) = 0 iff n is a power of 2.

Links

Max Alekseyev, Table of n, a(n) for n = 2..1000

Prog

(PARI) { a(n, m=n, s=2) = local(g); if(s==n, return(n%m)); g=factor(gcd(s, m)); for(i=1, matsize(g)[1], g[i, 2]=valuation(m, g[i, 1]); m\=g[i, 1]^g[i, 2]); g=prod(i=1, matsize(g)[1], g[i, 1]^g[i, 2]); lift( chinese( Mod(0, g), Mod(s, m)^a(n, eulerphi(m), s+1) )) }

Crossrefs

A variant of A092188.

Sequence in context: A143751 A353322 A158950 * A242667 A059581 A344319

Adjacent sequences: A213010 A213011 A213012 * A213014 A213015 A213016

Keyword

nonn

Author

Max Alekseyev, Jun 02 2012

Status

approved