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 A076803 Smallest multiple of n which is a reverse concatenation of n nonnegative consecutive numbers, or 0 if no such multiple exists. 1
 1, 10, 210, 5432, 43210, 543210, 2111019876, 98765432, 876543210, 9876543210, 918171615141312111019, 3121110198765432, 716151413121110198765, 7161514131211101987654, 41312111019876543210 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(20k)=a(50k)=0 for any k. On the other hand, a(n) is nonzero if n is not multiple of 10. - Max Alekseyev, Feb 15 2005 LINKS Table of n, a(n) for n=1..15. PROG (PARI) {len10(m) = ceil(log(m+1)/log(10))} {reverse(n) = m=0; while(n, m=m*10+(n%10); n\=10); return(m)} {a(n) = local(m); for(s=0, 10^6, m=0; for(i=0, n-1, m=m*10^len10(s+i)+s+i); m=reverse(m); if(s==0, m*=10); if(m%n==0, return(m)); if(n%10==0, return(0)))} (Alekseyev) CROSSREFS Cf. A077691. Sequence in context: A052245 A052246 A001450 * A120596 A238467 A254322 Adjacent sequences: A076800 A076801 A076802 * A076804 A076805 A076806 KEYWORD base,nonn AUTHOR Amarnath Murthy, Nov 16 2002 EXTENSIONS More terms from Max Alekseyev, Feb 15 2005 STATUS approved

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Last modified September 8 08:26 EDT 2024. Contains 375753 sequences. (Running on oeis4.)