A076645 - OEIS

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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.

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; 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	`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: A071797 A025481 A124171 * 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 Lewis (jblewis(AT)fas.harvard.edu), Nov 15 2006`

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Last modified February 15 18:22 EST 2012. Contains 205835 sequences.