This site is supported by donations to The OEIS Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A268354 Highest power of 7 dividing n. 2
 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 49, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 1, 49, 1, 1, 1, 1, 1, 1, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,7 COMMENTS The generalized binomial coefficients produced by this sequence provide an analog to Kummer's Theorem using arithmetic in base 7. LINKS Antti Karttunen, Table of n, a(n) for n = 1..20790 Tyler Ball, Tom Edgar, and Daniel Juda, Dominance Orders, Generalized Binomial Coefficients, and Kummer's Theorem, Mathematics Magazine, Vol. 87, No. 2, April 2014, pp. 135-143. Tom Edgar and Michael Z. Spivey, Multiplicative functions, generalized binomial coefficients, and generalized Catalan numbers, Journal of Integer Sequences, Vol. 19 (2016), Article 16.1.6. FORMULA a(n) = 7^valuation(n,7). a(n) = 7^A214411(n). Completely multiplicative with a(7) = 7, a(p) = 1 for prime p and p <> 7. - Andrew Howroyd, Jul 20 2018 EXAMPLE Since 14 = 7 * 2, a(14) = 7. Likewise, since 7 does not divide 13, a(13) = 1. MATHEMATICA 7^Table[IntegerExponent[n, 7], {n, 150}] (* Vincenzo Librandi, Feb 03 2016 *) PROG (Sage) [7^valuation(i, 7) for i in [1..100]] (MAGMA) [7^Valuation(n, 7): n in [1..150]]; // Vincenzo Librandi, Feb 03 2016 (PARI) a(n) = 7^valuation(n, 7) \\ Michel Marcus, Feb 05 2016 CROSSREFS Cf. A000420, A006519, A038500, A234957, A214411, A234959. Sequence in context: A074465 A081229 A109010 * A117825 A010143 A101027 Adjacent sequences:  A268351 A268352 A268353 * A268355 A268356 A268357 KEYWORD nonn,easy,mult AUTHOR Tom Edgar, Feb 02 2016 EXTENSIONS More terms from Antti Karttunen, Dec 22 2017 STATUS approved

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

Last modified January 20 17:05 EST 2019. Contains 319335 sequences. (Running on oeis4.)