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 A061955 Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 2 (most significant digit on right). 141
 1, 3, 7, 29, 375, 545, 971, 1643, 37801, 435805, 554423, 565947, 645915, 733533, 871927, 9703985 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This sequence differs from A029519 in that all least significant zeros are kept during concatenation. No more terms < 10^7. - Lars Blomberg, Aug 31 2011 LINKS EXAMPLE 7654321 -> (111)(011)(101)(001)(11)(01)(1) base 2 ->11101110100111011 base 2 = 122171 and 7 divides 122171. MATHEMATICA b = 2; c = {}; Select[Range[10^4], Divisible[FromDigits[c = Join[Reverse[IntegerDigits[#, b]], c], b], #] &] (* Robert Price, Mar 07 2020 *) PROG (PARI) is(n) = my(t=[]); for(k=1, n, t=concat(Vecrev(binary(k)), t)); if(Mod(subst(Pol(t), x, 2), n)==0, return(1), return(0)) \\ Felix FrÃ¶hlich, Jul 06 2017 CROSSREFS Cf. A029447-A029470, A029471-A029494, A029495-A029518, A029519-A029542, A061931-A061954, A061955-A061978. Sequence in context: A082096 A119325 A048722 * A113834 A057181 A333393 Adjacent sequences:  A061952 A061953 A061954 * A061956 A061957 A061958 KEYWORD nonn,base,more AUTHOR Larry Reeves (larryr(AT)acm.org), May 24 2001 EXTENSIONS Edited and updated by Larry Reeves (larryr(AT)acm.org), Apr 12 2002; Aug 25 2002 a(13)-a(16) from Lars Blomberg, Aug 31 2011 STATUS approved

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Last modified December 3 02:06 EST 2020. Contains 338898 sequences. (Running on oeis4.)