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A076645 Counts the ways to write 0 as 1 +- 2 +- 3 +- 4 +- ... +- k for some k, where signs alternate except that there is one instance of two consecutive positive terms. 0
1, 2, -3, 1, -2, 3, 4, -5, 6, -7, 1, -2, 3, -4, 5, 6, -7, 8, -9, 10, -11, 1, -2, 3, -4, 5, -6, 7, 8, -9, 10, -11, 12, -13, 14, -15, 1, -2, 3, -4, 5, -6, 7, -8, 9, 10, -11, 12, -13, 14, -15, 16, -17, 18, -19, 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11, 12, -13, 14, -15, 16, -17, 18, -19, 20, -21, 22, -23, 1, -2, 3, -4, 5, -6, 7, -8, 9, -10, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

COMMENTS

Derived from an attempt to demonstrate that the fundamental state of a ferromagnetic systems defined with the Hamiltonian defined in "A measure for the complexity of Boolean functions" has energy equal to -0.5.

REFERENCES

L. Franco, Long-range ferromagnetic model in the hypercell. In preparation

LINKS

Table of n, a(n) for n=3..91.

L. Franco, A measure for the complexity of Boolean functions related to their implementation in neural networks (2001).

EXAMPLE

0=1+2-3, 0=1-2+3+4-5+6-7, 0=1-2+3-4+5+6-7+8-9+10-11, ...

CROSSREFS

Sequence in context: A124171 A276146 A210530 * A011448 A174981 A067280

Adjacent sequences:  A076642 A076643 A076644 * A076646 A076647 A076648

KEYWORD

sign

AUTHOR

Leonardo Franco (Leonardo.Franco(AT)psy.ox.ac.uk), Oct 23 2002

EXTENSIONS

Edited by Joel B. Lewis, Nov 15 2006

STATUS

approved

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Last modified May 24 04:25 EDT 2019. Contains 323528 sequences. (Running on oeis4.)