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.

A361978 Complement of A361337.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 46, 47, 48, 49, 51, 53, 57, 61, 62, 63, 64, 66, 67, 68, 71, 72, 73, 74, 75, 76, 77, 79, 81, 82, 83, 84, 86, 88, 89, 91, 92, 93, 94, 97, 98, 99, 111, 112, 113, 114, 116
Offset: 1

Views

Author

Michael S. Branicky, Apr 02 2023

Keywords

Comments

More than the usual number of terms are shown to distinguish the sequence from A034048.
Appears to be finite with 219 members, the largest being 3111.

Crossrefs

Subsequence of A052382.

Programs

  • PARI
    A361978=select( {is_A361978(n)=vecmin(digits(n))&& !for(p=1, logint(n, 10), is_A361978(vecprod(divrem(n, 10^p)))|| return)}, [1..10^5]) \\ Conjecturedly the full list: no terms between 3112 and 10^5. - M. F. Hasler, Apr 05 2023
  • Python
    def ok(n):
        if n < 10: return n != 0
        s = str(n)
        if "0" in s: return False
        return all(ok(int(s[:i])*int(s[i:])) for i in range(1, len(s)))
    print([k for k in range(117) if ok(k)]) # Michael S. Branicky, Apr 02 2023