OFFSET
1,1
COMMENTS
a(1) = 12, a(n) = smallest concatenation of next successive natural numbers that is a multiple of n, or 0 if no such concatenation exists.
a(1) = 1 would have given a trivial sequence 1,2,3,4,5....
Every partial concatenation is a left substring of the concatenation of natural numbers.
FORMULA
a(n) = A077294(n)*n. - Jinyuan Wang, May 16 2020
EXAMPLE
a(2) = 34 = 2*17; a(7) = 17181920 = 7*2454560.
PROG
(PARI) lista(nn) = {my(k=0, m); for(n=1, nn, m=k++; while(m%n>0 || m==n, m=eval(Str(m, k++))); print1(m, ", ")); } \\ Jinyuan Wang, May 16 2020
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Nov 03 2002
EXTENSIONS
Corrected and extended by Ray Chandler, Oct 18 2003
STATUS
approved