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.

A006055 Primes with consecutive (ascending) digits.

Original entry on oeis.org

2, 3, 5, 7, 23, 67, 89, 4567, 78901, 678901, 23456789, 45678901, 9012345678901, 789012345678901, 56789012345678901234567890123, 90123456789012345678901234567, 678901234567890123456789012345678901
Offset: 1

Views

Author

N. J. A. Sloane, Richard C. Schroeppel

Keywords

References

  • J. S. Madachy, Consecutive-digit primes - again, J. Rec. Math., 5 (No. 4, 1972), 253-254.
  • Thomas E. Moore, A Note on the Distribution of Primes in Arithmetic Progressions, J. Rec. Math., 5 (1972), 253-254.
  • R. C. Schroeppel, personal communication, 1991.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • D. Zwillinger, Consecutive-Digit Primes - In Different Bases, J. Rec. Math., 10 (1972), 32-33.

Crossrefs

Programs

  • Mathematica
    f[n_] := Block[{u = Range@n, t = Table[1, {n}]}, Select[ Drop[ Union@ Flatten@ Table[ FromDigits[ Mod[u + i*t, 10]], {i, 10}], 2], PrimeQ@# &]]; Array[f, 35] // Flatten (* Robert G. Wilson v, Jul 05 2006 *)
  • Python
    from sympy import isprime
    from itertools import count, islice
    def bgen(): yield from (int("".join(str((s0+i)%10) for i in range(d))) for d in count(1) for s0 in range(1, 10))
    def agen(): yield from filter(isprime, bgen())
    print(list(islice(agen(), 18))) # Michael S. Branicky, May 26 2022

Extensions

a(17) from Robert G. Wilson v, Jul 05 2006
Entry revised by N. J. A. Sloane, Feb 07 2007

A120804 Primes with consecutive digits descending.

Original entry on oeis.org

2, 3, 5, 7, 43, 109, 10987, 76543, 10987654321098765432109876543210987, 4321098765432109876543210987654321098765432109876543210987654321
Offset: 1

Views

Author

Robert G. Wilson v, Jul 05 2006

Keywords

Comments

Digits can be in descending order. After 0 comes 9.
a(15) has 1053 digits. - Michael S. Branicky, Aug 05 2022

Crossrefs

Programs

  • Mathematica
    f[n_] := Block[{d = Reverse@ Range@n, t = Table[1, {n}]}, Select[ Drop[ Union@ Flatten@ Table[ FromDigits[ Mod[d + i*t, 10]], {i, 10}], 2], PrimeQ@# &]]; Array[f, 1000] // Flatten
  • Python
    from sympy import isprime
    from itertools import count, islice
    def bgen(): yield from (int("".join(str((s0-i)%10) for i in range(d))) for d in count(1) for s0 in range(1, 10))
    def agen(): yield from filter(isprime, bgen())
    print(list(islice(agen(), 10))) # Michael S. Branicky, Aug 05 2022

Extensions

Corrected by Paul Tek, May 08 2013
Showing 1-2 of 2 results.