A328758 Lexicographically earliest sequence of distinct positive numbers such that for any n > 0, the first nonzero digit of a(n+1)/a(n) is "7".

1, 7, 5, 35, 25, 18, 13, 10, 70, 49, 36, 26, 2, 14, 11, 8, 6, 42, 3, 21, 15, 105, 74, 52, 4, 28, 20, 140, 98, 69, 50, 37, 27, 19, 133, 94, 66, 47, 33, 24, 17, 12, 9, 63, 45, 32, 23, 161, 113, 80, 56, 40, 29, 22, 16, 112, 79, 57, 41, 30, 210, 147, 103, 73, 53

Offset

1,2

Comments

In other words, for any n > 0, we have an integer k such that floor(10^k * a(n+1)/a(n)) = 7.

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Example

The first terms, alongside a(n+1)/a(n), are:
  n   a(n)  a(n+1)/a(n)
  --  ----  -----------
   1     1  7
   2     7  0.714285...
   3     5  7
   4    35  0.714285...
   5    25  0.72
   6    18  0.722222...
   7    13  0.769230...
   8    10  7
   9    70  0.7
  10    49  0.734693...
  11    36  0.722222...
  12    26  0.076923...

Crossrefs

See A328752 for similar sequences.

Sequence in context: A213243 A185269 A344917 * A070426 A341431 A142883

Adjacent sequences: A328755 A328756 A328757 * A328759 A328760 A328761

Keyword

nonn,base

Author

Rémy Sigrist, Oct 27 2019

Status

approved