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A350537
Smallest number m > 1 such that (2n+1)*m = A350536(n) contains only odd digits.
2
3, 3, 3, 5, 11, 3, 3, 5, 3, 3, 15, 5, 3, 5, 11, 3, 3, 5, 3, 3, 13, 13, 3, 11, 11, 3, 3, 13, 3, 3, 13, 5, 3, 5, 11, 5, 7, 5, 7, 5, 17, 11, 7, 11, 11, 21, 15, 21, 35, 101, 11, 5, 3, 5, 11, 3, 3, 5, 3, 3, 11, 11, 3, 11, 15, 3, 3, 13, 7, 7, 11, 5, 11, 5, 13, 5, 9, 5, 47, 5
OFFSET
0,1
COMMENTS
Record values of a(n) are 3, 5, 11, 15, 17, 21, 35, 101, 155, ...
LINKS
FORMULA
a(n) = A350536(n) / (2n+1).
EXAMPLE
The smallest proper multiple of 21 = 2*10+1 with only odd digits is A350536(10) = 315, as 315 = 21 * 15, a(10) = 15.
MATHEMATICA
Table[m=2; While[Or@@EvenQ[IntegerDigits[(2n+1)*++m]]]; m, {n, 0, 79}] (* Giorgos Kalogeropoulos, Jan 12 2022 *)
PROG
(PARI) isok(k) = my(d=digits(k)); #d == #select(x->((x%2)==1), d);
a(n) = my(k=6*n+3); while (!isok(k), k+=4*n+2); k/(2*n+1); \\ Michel Marcus, Jan 12 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Bernard Schott, Jan 12 2022
EXTENSIONS
More terms from Michel Marcus, Jan 12 2022
STATUS
approved