OFFSET
1,1
COMMENTS
If we want the sequence to be infinite, we cannot extend it with terms < 10. After a(28) = 499999999999999999999 the terms become exponentially huge and impossible to present here.
LINKS
Eric Angelini, SuperSums, SuperProducts, personal blog.
EXAMPLE
digitsum a(1) + digitsum a(2) = 1 + 0 + 1 + 3 = 5 and 5 divides exactly a(1) = 10;
digitsum a(2) + digitsum a(3) = 1 + 3 + 1 + 8 = 13 and 13 divides exactly a(2) = 13;
digitsum a(3) + digitsum a(4) = 1 + 8 + 2 + 7 = 18 and 18 divides exactly a(3) = 18;
digitsum a(4) + digitsum a(5) = 2 + 7 + 9 + 9 = 27 and 27 divides exactly a(4) = 27;
digitsum a(5) + digitsum a(6) = 9 + 9 + 6 + 9 = 33 and 33 divides exactly a(5) = 99; etc.
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Eric Angelini, Jul 13 2023
STATUS
approved