

A036442


a(n) = 2^((n1)*(n+2)/2).


12



1, 4, 32, 512, 16384, 1048576, 134217728, 34359738368, 17592186044416, 18014398509481984, 36893488147419103232, 151115727451828646838272, 1237940039285380274899124224, 20282409603651670423947251286016, 664613997892457936451903530140172288
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OFFSET

1,2


COMMENTS

Number of redundant paths for a faulttolerant ATM switch.
Hankel transform (see A001906 for definition ) of A001850, A006139, A084601; also Hankel transform of the sequence 1, 0, 4, 0, 24, 0, 160, 0, 1120, ... (A059304 with interpolated zeros).  Philippe Deléham, Jul 03 2005
Hankel transform of A109980. Unsigned version of A127945.  Philippe Deléham, Dec 11 2008
a(n) = the multiplicative Wiener index of the wheel graph with n+3 vertices. The multiplicative Wiener index of a connected simple graph G is defined as the product of the distances between all pairs of distinct vertices of G. The wheel graph with n+3 vertices has (n+3)(n+2)/2 pairs of distinct vertices, of which 2(n+2) are adjacent; each of the remaining (n+2)(n1)/2 pairs are at distance 2; consequently, the multiplicative Wiener index is 2^((n1)(n+2)/2) = a(n).  Emeric Deutsch, Aug 17 2015


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..80
P. Barry, Comparing two matrices of generalized moments defined by continued fraction expansions, arXiv preprint arXiv:1311.7161, 2013 and J. Int. Seq. 17 (2014) # 14.5.1
P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.
I. Gutman, W. Linert, I. Lukovits, and Z. Tomovic, The multiplicative version of the Wiener index, J. Chem. Inf. Comput. Sci., 40, 2000, 113116.
C. Lo and C. Chiu, A FaultTolerant Architecture for ATM Networks, 20th IEEE Conf. Local Computer Networks, 1995, pp. 2936
Index to divisibility sequences


FORMULA

a(1) = 1, a(n) = a(n1) * 2^n.  Vincenzo Librandi, Oct 24 2012


MATHEMATICA

Table[2^((n1) * (n+2)/2), {n, 1, 30}] (* Vincenzo Librandi, Oct 24 2012 *)


PROG

(MAGMA) I:=[1]; [n le 1 select I[n] else Self(n1)*2^n: n in [1..20]]; // Vincenzo Librandi, Oct 24 2012
(PARI) a(n)=2^((n1)*(n+2)/2) \\ Charles R Greathouse IV, Oct 24 2012
(Maxima) A036442[n]:=2^((n1)*(n+2)/2)$
makelist(A036442[n], n, 1, 30); /* Martin Ettl, Oct 29 2012 */


CROSSREFS

Sequence in context: A140179 A118990 A127945 * A186339 A086899 A219149
Adjacent sequences: A036439 A036440 A036441 * A036443 A036444 A036445


KEYWORD

easy,nonn


AUTHOR

Abdallah Rayhan (rayhan(AT)engr.uvic.ca)


STATUS

approved



