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A036057 Friedman numbers: can be written in a nontrivial way using their digits and the operations + - * / ^ and concatenation of digits (but not of results). 9
25, 121, 125, 126, 127, 128, 153, 216, 289, 343, 347, 625, 688, 736, 1022, 1024, 1206, 1255, 1260, 1285, 1296, 1395, 1435, 1503, 1530, 1792, 1827, 2048, 2187, 2349, 2500, 2501, 2502, 2503, 2504, 2505, 2506, 2507, 2508, 2509, 2592, 2737, 2916, 3125, 3159 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Mitchell's and Wilson's lists both lack two terms, 16387 = (1-6/8)^(-7)+3 and 41665 = 641*65. - Giovanni Resta, Dec 14 2013

REFERENCES

M. Brand, Friedman numbers have density 1, Discrete Applied Mathematics, Volume 161, Issues 16-17, November 2013, Pages 2389-2395.

LINKS

Kerry Mitchell, Table of n, a(n) for n = 1..842 [taken from Eric Friedman's page]

Erich Friedman, Friedman Numbers

Robert G. Wilson v, Table of n, a(n) with factorizations for n=1..844

Giovanni Resta, Friedman numbers Friedman numbers and expressions up to 10^6

Index entries for Four 4's problem

FORMULA

a(n) ~ n. - Charles R Greathouse IV, Jun 04 2013

EXAMPLE

E.g. 153=51*3, 736=3^6+7. Not 26 = 2 6, that's trivial.

CROSSREFS

Cf. A080035, A156954, A046469.

Sequence in context: A126412 A078815 A206472 * A083509 A213445 A031151

Adjacent sequences:  A036054 A036055 A036056 * A036058 A036059 A036060

KEYWORD

base,nonn

AUTHOR

Erich Friedman

EXTENSIONS

Corrected broken URL. Added cross-reference to A156954 R. J. Mathar, Feb 20 2009

STATUS

approved

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Last modified April 16 00:31 EDT 2014. Contains 240534 sequences.