cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A352024 Largest digit in the decimal expansion of 1/A352023(n).

Original entry on oeis.org

5, 3, 2, 8, 7, 8, 8, 5, 8, 8, 8, 8
Offset: 1

Views

Author

Bernard Schott, Mar 01 2022

Keywords

Comments

All terms are < 9.
A352023(13) <= 5363222357 and A352023(14) <= 77843839397, in both cases, the corresponding largest digit in the decimal expansion of the inverse is 8.

Examples

			A352023(5) = 37, the largest digit in the decimal expansion of 1/37 = 0.027027027027027... is 7, hence a(5) = 7.
		

Crossrefs

Formula

a(n) = A333236(A352023(n)). - Amiram Eldar, Mar 02 2022

A187614 Primes p such that the decimal representation of 1/p does not contain every digit 0-9.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 31, 37, 41, 43, 67, 73, 79, 101, 137, 239, 271, 353, 449, 757, 859, 1933, 4649, 8779, 9091, 9901, 21401, 21649, 25601, 27961, 52579, 62003, 123551, 333667, 513239, 538987, 909091, 1676321, 2071723, 2906161, 5882353, 10838689, 35121409, 52986961, 99990001, 265371653, 1056689261, 1058313049, 1360682471
Offset: 1

Views

Author

Michel Lagneau, Mar 12 2011

Keywords

Comments

Every repunit prime (A004022) is here. There are 113 terms of A046107, having periods of up to 256, that are here. The only known unique-period prime (A007615) not here is the one having period 92092. Is this sequence finite? - T. D. Noe, Mar 13 2011

Examples

			4649 is in the sequence because 1/4649 = 0.00021510002151000215.... contain
  only the digits 0, 1, 2 and 5.
		

Crossrefs

Cf. A187372.
Cf. A352023 (does not contain digit 9)

Programs

  • Mathematica
    Join[{2, 3, 5}, Select[Prime[Range[4, 10000]], Length[Union[RealDigits[1/#][[1, 1]]]] < 10 &]]
  • Python
    from sympy import n_order, nextprime
    from itertools import islice
    def A187614_gen(): # generator of terms
        yield from (2,3,5)
        p = 7
        while True:
            if len(set('0'+str(10**(n_order(10, p))//p))) < 10:
                yield p
            p = nextprime(p)
    A187614_list = list(islice(A187614_gen(),20)) # Chai Wah Wu, Mar 03 2022

Extensions

Extended by T. D. Noe, Mar 12 2011
Showing 1-2 of 2 results.