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A284814
Least number k such that k mod (2, 3, 4, ... , n+1) = (d_1, d_2, ..., d_n), where d_1 , d_2, …, d_n are the digits of n, with MSD(n) = d_1 and LSD(n) = d_n. 0 if such a number does not exist.
0
1, 0, 0, 0, 11311, 0, 1032327, 11121217, 101033565, 0, 10333633323, 0, 0, 11121314781937, 0
OFFSET
1,5
COMMENTS
Suggested by Francis Maleval in Linkedin "Number Theory" group.
EXAMPLE
a(11) = 10333633323 because:
10333633323 mod 2 = 1, 10333633323 mod 3 = 0, 10333633323 mod 4 = 3,
10333633323 mod 5 = 3, 10333633323 mod 6 = 3, 10333633323 mod 7 = 6,
10333633323 mod 8 = 3, 10333633323 mod 9 = 3, 10333633323 mod 10 = 3,
10333633323 mod 11 = 2, 10333633323 mod 12 = 3.
MAPLE
P:=proc(q) local a, d, j, k, n, ok; for k from 1 to q do d:=0; for n from 10^(k-1) to 10^k-1 do
ok:=1; a:=n; for j from 1 to ilog10(n)+1 do if (a mod 10)<>n mod ((ilog10(n)+2-j)+1)
then ok:=0; break; else a:=trunc(a/10); fi; od; if ok=1 then print(n); d:=1; break; fi; od;
if n=10^k and d=0 then print(0); fi; od; end: P(20);
CROSSREFS
Cf. A284815.
Sequence in context: A112441 A104017 A317400 * A228627 A178581 A178583
KEYWORD
nonn,base,hard,more
AUTHOR
Paolo P. Lava, Apr 10 2017
EXTENSIONS
a(12)-a(15) from Giovanni Resta, Apr 10 2017
STATUS
approved