

A144378


Initial term of a series of exactly n consecutive nonNiven (or Harshad) numbers.


1



11, 22, 37, 136, 13, 64, 73, 163, 91, 1730, 289, 1639, 379, 1660, 2737, 919, 559, 14878, 7561, 5671, 9753, 2890, 7777, 4888, 5785, 5590, 27973, 47872, 28681, 22681, 3785, 36184, 46281, 71281, 6481, 48952, 48763, 64978, 119773, 69782, 77881, 55973
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OFFSET

1,1


COMMENTS

Multiples of 18 seem to be the high water marks, while terms of the form 18n  1 seem to be the valleys of this sequence.
Many terms end in '81' for some reason.
This sequence is analog to A060159 with nonNiven numbers.
This sequence is infinite, as opposed as A060159.


LINKS

Klaus Brockhaus, Table of n, a(n) for n=1..125
Eric Weisstein's World of Mathematics, Harshad Number


EXAMPLE

a(5) = 13 since 13, 14, 15, 16 and 17 are all nonNiven numbers and this is the first occurrence of exactly 5 nonNiven numbers.


PROG

(PARI) digitsum(n) = {local(s=0); while(n, s+=n%10; n\=10); s}
{m=120000; z=42; w=vector(z); n=1; while(n<=m, while(n%digitsum(n)==0, n++); a=n; c=0; while(n%digitsum(n)>0, n++; c++); if(c<=z&&w[c]==0, w[c]=a)); j=1; while(j<=z&&w[j]>0, print1(w[j], ", "); j++)} /* Klaus Brockhaus, Sep 24 2008 */


CROSSREFS

Cf. A005349, A082516, A060159, A144261, A144262.
Sequence in context: A109016 A084025 A061157 * A026037 A266088 A122613
Adjacent sequences: A144375 A144376 A144377 * A144379 A144380 A144381


KEYWORD

base,hard,nonn


AUTHOR

Sergio Pimentel, Sep 18 2008


EXTENSIONS

a(2), a(22), a(42) corrected by Klaus Brockhaus, Sep 24 2008


STATUS

approved



