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 A100200 Decimal Goedelization of antitheorems from propositional calculus, in Richard C. Schroeppel's metatheory of A101273. 5
 151, 252, 1431, 1831, 2432, 2832, 3141, 3181, 3242, 3282, 11511, 12512, 14151, 15141, 15331, 15910, 21521, 22522, 24252, 25242, 25332, 25920, 31531, 32532, 33151, 33252, 91051, 91510, 92052, 92520, 114311, 118311, 124312, 128312, 141431, 141831, 142431 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Blocks of 1's and 2s are variables: A = 1, B = 2, C = 11, D = 12, E = 21, ... Not (also written -) = 3; And = 4; Xor = 5; Or = 6; Implies = 7; Equiv = 8; Left Parenthesis = 9; Right Parenthesis = 0. Operator binding strength is in numerical order, Not > And > ... > Equiv. The non-associative "Implies" is evaluated from Left to Right; A->B->C = is interpreted (A->B)->C. Redundant parentheses are permitted, so long as they are balanced and centered on a valid variable or sentential formula and not on the null character. Besides A101273, there can also be the subsequence of theorems that can be proved within the more restricted Intuitionist logic; the sequence of well-formed formulas whose truth value is contingent on the truth values of their variables; and many others. As with A101273, I conjecture that a power law approximates the number of integers in this sequence, where the number with N digits is approximately N to the power of some real number D. Comment from Ed Brims (ejbrims(AT)hotmail.com), Aug 18 2008: Quite interestingly, this sequence is quoted (in its original incorrect form) in the novel "The End of Mr Y" by Scarlett Thomas, towards the end of Chapter 12. REFERENCES Goedel, K. On Formally Undecidable Propositions of Principia Mathematica and Related Systems. New York: Dover, 1992. Hofstadter, D. R. Goedel, Escher, Bach: An Eternal Golden Braid. New York: Vintage Books, p. 17, 1989. Kleene, S. C. Introduction to Metamathematics. Princeton, NJ: Van Nostrand, p. 39, 1964. Scarlett Thomas, "The End of Mr Y", Harcourt Books. LINKS Charles R Greathouse IV, Table of n, a(n) for n=1..10000 Eric Weisstein's World of Mathematics, Propositional Calculus Eric Weisstein's World of Mathematics, Connective. See this for table of functions (and their notations) which corresponds to English conjunctions such as "and," "or," "not," etc. that takes one or more truth values as input and returns a single truth value as output. This includes ones used in A101273. Eric Weisstein et al., Goedel Number. FORMULA Well-formed formulas that are always false (i.e. negations of theorems) represented as decimal integers in Richard C. Schroeppel's metatheory of A101273. EXAMPLE 1431 corresponds to the sentence which violates the Law of the Excluded Middle: A ^ -A. 33252 corresponds to the sentence, with square brackets being implicit parentheses, [ --B ] xor B. 118311 corresponds to this sentence asserting the equivalence of the 3rd variable with its negation, C = -C. CROSSREFS Cf. A101273, A101248. Sequence in context: A152310 A276264 A070182 * A142575 A142657 A142760 Adjacent sequences:  A100197 A100198 A100199 * A100201 A100202 A100203 KEYWORD nonn,base AUTHOR Jonathan Vos Post, Dec 27 2004 EXTENSIONS Sequence and example corrected by Charles R Greathouse IV, Oct 06 2009 Entries replaced by values from b-file. - N. J. A. Sloane, Oct 04 2010 STATUS approved

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Last modified January 18 16:40 EST 2019. Contains 319271 sequences. (Running on oeis4.)