The OEIS is supported by the many generous donors to the OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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] MAPLE q:= n-> andmap(t-> not 0 in convert(t, base, 10), [2^n, 5^n]): select(q, [\$0..40])[];  # Alois P. Heinz, Feb 03 2022 MATHEMATICA Range@(10^5) // Select[Last@DigitCount@(5^#) == 0 &] // Select[Last@DigitCount@(2^#) == 0 &] (* Hans Rudolf Widmer, Feb 02 2022 *) 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 24 18:55 EDT 2022. Contains 356949 sequences. (Running on oeis4.)