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A028401 The (2^n+1)-th triangular number (cf. A000217). +0
3
3, 6, 15, 45, 153, 561, 2145, 8385, 33153, 131841, 525825, 2100225, 8394753, 33566721, 134242305, 536920065, 2147581953, 8590131201, 34360131585, 137439739905, 549757386753, 2199026401281, 8796099313665, 35184384671745 (list; graph; listen)
OFFSET

2,1

COMMENT

Number of types of Boolean functions of n variables under a certain group.

Also the number of ordered decompositions of 2^n into 3 nonnegative integers (e.g. 2=0+0+2=0+2+0=2+0+0=1+1+0=1+0+1=0+1+1). - Tamas Kalmar-Nagy (integers(AT)kalmarnagy.com), Aug 02 2007

REFERENCES

I. Strazdins, Universal affine classification of Boolean functions, Acta Applic. Math. 46 (1997), 147-167.

LINKS

Index entries for sequences related to Boolean functions

FORMULA

(3/8)*2^n + (1/32)*4^n + 1. a(n) = 3*A007581(n-2) = 3/4*A060919(n-1). - Ralf Stephan (ralf(AT)ark.in-berlin.de), Aug 23 2003

a(n) = (2^n+1)(2^n+2)/2 - Tamas Kalmar-Nagy (integers(AT)kalmarnagy.com), Aug 02 2007

CROSSREFS

Equals 2 * A036562(n-4) - 1, n>3.

Cf. A000217.

Sequence in context: A005368 A067771 A056382 this_sequence A005655 A051169 A051610

Adjacent sequences: A028398 A028399 A028400 this_sequence A028402 A028403 A028404

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 24 2000

Simpler definition from Tamas Kalmar-Nagy (integers(AT)kalmarnagy.com), Aug 02 2007

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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