|
| |
|
|
A100402
|
|
Digital root of 4^n.
|
|
0
| |
|
|
1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7, 1, 4, 7
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Equals A141725 (1, 13, 61, 253, 1021, 4093, 16381, ...) mod 9 . - Paul Curtz (bpcrtz(AT)free.fr), Sep 15 2008
4^n mod 9. [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 25 2009]
Except for the first term, sequence is the reduced sum of A180364. [From Odimar Fabeny (aifab(AT)yahoo.com.br), Sep 13 2010]
|
|
|
FORMULA
| a(n)= a(n-3). G.f.: (1+4*x+7*x^2)/ ((1-x) * (1+x+x^2)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 13 2010]
|
|
|
EXAMPLE
| 4^2 = 16, droot(16) = 7, the third entry.
|
|
|
PROG
| (PARI) f(n, m) = for(x=0, n, print1(droot(m^x)", ")) droot(n) = \ the digital root of a number. { local(x); x= n%9; if(x>0, return(x), return(9)) }
(Other) sage: [power_mod(4, n, 9)for n in xrange(0, 105)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 25 2009]
|
|
|
CROSSREFS
| Cf. A180364. [From Odimar Fabeny (aifab(AT)yahoo.com.br), Sep 13 2010]
Sequence in context: A123734 A011519 A131594 * A135004 A086234 A016490
Adjacent sequences: A100399 A100400 A100401 * A100403 A100404 A100405
|
|
|
KEYWORD
| easy,nonn,base
|
|
|
AUTHOR
| Cino Hilliard (hillcino368(AT)gmail.com), Dec 31 2004
|
| |
|
|
