0,1

Same as Pisot sequences E(3,6), L(3,6), P(3,6), T(3,6). See A008776 for definitions of Pisot sequences.

Numbers n such that P[phi[n]]=phi[P[n]], where P[x] is the largest prime-factor of x; A006530[A000010(n)]=A000010[A006530(n)]=2. - Labos E. (labos(AT)ana.sote.hu), May 07 2002

Also least number m such that 2^n is the smallest proper divisor of m which is also a suffix of m in binary representation, see A080940. - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Feb 25 2003

Length of the period of the sequence Fibonacci(k) (mod 2^(n+1)). - Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 12 2003

An autocopy sequence: its first differences are the sequence itself. - Alexandre Wajnberg & Eric Angelini (alexandre.wajnberg(AT)ulb.ac.be), Sep 07 2005

Subsequence of A122132. - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Aug 21 2006

Apart from the first term, a subsequence of A124509. - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Nov 04 2006

Total number of Latin n-dimentional hypercubes (Latin polyhedra) of order 3. - Kenji Ohkuma (k-ookuma(AT)ipa.go.jp), Jan 10 2007

Number of different ternary hypercubes of dimension n. - Edwin Soedarmadji (edwin(AT)systems.caltech.edu), Dec 10 2005

For n>=1, a(n) is equal to the number of functions f:{1,2,...,n+1}->{1,2,3} such that for fixed, different x_1, x_2,...,x_n in {1,2,...,n+1} and fixed y_1, y_2,...,y_n in {1,2,3} we have f(x_i)<>y_i, (i=1,2,...,n). - Milan R. Janjic (agnus(AT)blic.net), May 10 2007

T. Ito, Method, equipment, program and storage media for producing tables, Publication number JP2004-272104A, Japan Patent Office(written in Japanese, a(2)=12,a(3)=24,a(4)=48,a(5)=96,a(6)=192,a(7)=384(a(7)=284 was corrected)).

Kenji Ohkuma, Atsuhiro Yamagishi and Toru Ito, Cryptography Research Group Technical report, IT Security Center, Information-Technology Promotion Agency, JAPAN.

E. Soedarmadji, Latin Hypercubes and MDS Codes, preprint, 2005.

Tanya Khovanova, Recursive Sequences

G.f.: 3/(1-2*x)

a(n)=2a(n-1), n>0; a(0)=3.

a(n) = sum(k=0, n, (-1)^(k reduced (mod 3))*C(n, k)) - Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 20 2002

a(n) = A118416(n+1,2) for n>1. - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Apr 27 2006

a(n)=A000079(n)+A000079(n+1). - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 12 2007

a:=n->sum(binomial(n, 2*j)+binomial(n, j), j=0..n): seq(a(n), n=1..34); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 12 2007

(PARI) a(n)=3*2^n

Essentially same as A003945 and A042950.

Row sums of (5, 1)-Pascal triangle A093562 and of (1, 5) Pascal triangle A096940.

Cf. A002860, A098679, A100540, A124508.

Cf. Latin squares: A000315, A002860, A003090, A040082, A003191; Latin cubes: A098843, A098846, A098679, A099321.

Cf. A000079.

Sequence in context: A046944 A122391 A003945 this_sequence A049942 A099844 A084717

Adjacent sequences: A007280 A007281 A007282 this_sequence A007284 A007285 A007286

easy,nonn

njas