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 A060159 Initial term of a series of exactly n consecutive Harshad or Niven numbers (a Harshad number is such that is divided by the sum of its digits). 13
 12, 20, 110, 510, 131052, 12751220, 10000095, 2162049150, 124324220, 1, 920067411130599, 43494229746440272890, 12100324200007455010742303399999999999999999990, 4201420328711160916072939999999999999999999999999999999999999996 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Cooper and Kennedy (1993) proved that this sequence contains 20 terms. - Sergio Pimentel, Sep 18 2008 a(16) = 50757686696033684694106416498959861492*10^280 - 9 and a(17) = 14107593985876801556467795907102490773681*10^280 - 10. - Max Alekseyev, Apr 07 2013 REFERENCES J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 110, p. 39, Ellipses, Paris 2008. LINKS C. N. Cooper and R. E. Kennedy, On consecutive Niven numbers, Fibonacci Quart, (1993) 21, 146-151. H. G. Grundman, Sequences of consecutive n-Niven numbers, Fibonacci Quarterly, (1994), 32 (2): 174-175. B. Wilson, Construction of 2n Consecutive n-Niven Numbers, Fibonacci Quarterly, (1997), 35, 122-128. Carlos Rivera, Puzzle 129. Earliest sets of K consecutive Harshad Numbers, The Prime Puzzles and Problems Connection. EXAMPLE a(3)=110 since 110 is divisible by 2, 111 is divisible by 3, 112 is divisible by 4 but 113 is not divisible by 5. CROSSREFS Cf. A005349. Sequence in context: A181701 A025104 A163323 * A167351 A231400 A231467 Adjacent sequences: A060156 A060157 A060158 * A060160 A060161 A060162 KEYWORD fini,hard,nonn,base AUTHOR Carlos Rivera, Mar 12 2001 EXTENSIONS a(8) is found by Jud McCranie, Nov 13 2001 a(11)-a(13) are found by Giovanni Resta, Feb 21 2008 a(14), a(16)-a(17) from Max Alekseyev, Apr 07 2013 STATUS approved

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Last modified February 3 04:55 EST 2023. Contains 360024 sequences. (Running on oeis4.)