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A073866
a(n) is the smallest composite number with the sum of digits = the n-th composite number.
1
4, 6, 8, 9, 28, 39, 68, 69, 88, 99, 299, 399, 589, 699, 799, 899, 999, 2899, 3999, 5999, 6999, 7999, 9899, 9999, 29999, 39999, 58999, 69999, 89999, 99999, 299899, 399999, 499999, 689999, 699999, 889999, 999999, 1999999, 3899999, 3999999, 5899999, 6999999, 8999999, 9999999
OFFSET
1,1
EXAMPLE
a(5) = 28, because 10 is the 5th composite, and 28 is the first composite with sum of digits equal to 10. - Michel Marcus, May 19 2014
PROG
(PARI) lista(nn) = {vn = vector(nn, i, i); vc = select(x->iscomp(x), vn); vsd = vector(#vc, i, sumdigits(vc[i])); for (i=1, #vc, print1(vc[select(x->(x==vc[i]), vsd, 1)[1]], ", "); ); } \\ Michel Marcus, May 19 2014
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Aug 15 2002
EXTENSIONS
More terms from Michel Marcus, May 19 2014
STATUS
approved