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 A007496 Numbers n such that the decimal expansions of 2^n and 5^n contain no 0's (probably 33 is last term). (Formerly M0497) 28
 0, 1, 2, 3, 4, 5, 6, 7, 9, 18, 33 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Intersection of A007377 and A008839. - Lekraj Beedassy, Jul 27 2004 From Jonathan Vos Post, Jul 20 2005: (Start) Equivalently, numbers n such that 10^n is the product of two integers without any zero digits. 10^0 = 1 * 1 10^1 = 2 * 5 10^2 = 4 * 25 10^3 = 8 * 125 10^4 = 16 * 625 10^5 = 32 * 3125 10^6 = 64 * 15625 10^7 = 128 * 78125 10^9 = 512 * 1953125 10^18 = 262144 * 3814697265625 10^33 = 8589934592 * 116415321826934814453125. (End) Searched for n up to 10^10. - David Radcliffe, Dec 27 2015 REFERENCES J. S. Madachy, Madachy's Mathematical Recreation, "#2. Number Toughies", pp. 126-8, Dover NY 1979. C. S. Ogilvy and J. T. Anderson, Excursions in Number Theory. Oxford Univ. Press, 1966, p. 89. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Leroy C. Dalton & Henry D. Snyder, Topics for Mathematics Clubs, pp. 68-69, NCTM Reston VA 1983. C. S. Ogilvy and J. T. Anderson, Excursions in Number Theory, Oxford Univ. Press, 1966, p. 89. (Annotated scanned copy). W. Schneider, NoZeros: Powers n^k without Digit Zero [Cached copy] PROG (PARI) isok(n) = vecmin(digits(2^n)) && vecmin(digits(5^n)); \\ Michel Marcus, Dec 28 2015 CROSSREFS Cf. A007377, A008839. Sequence in context: A048319 A037405 A048333 * A082274 A029804 A084690 Adjacent sequences:  A007493 A007494 A007495 * A007497 A007498 A007499 KEYWORD fini,nonn,full,base AUTHOR EXTENSIONS Edited by N. J. A. Sloane, Oct 24 2009 at the suggestion of M. F. Hasler STATUS approved

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Last modified October 20 21:32 EDT 2020. Contains 337910 sequences. (Running on oeis4.)