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.

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A358353 Numbers that are not of the form m + (sum of digits of m) + (product of digits of m) for any m.

Original entry on oeis.org

1, 2, 4, 5, 7, 8, 10, 13, 16, 19, 25, 28, 31, 36, 37, 39, 40, 41, 45, 47, 49, 51, 52, 57, 59, 60, 61, 64, 65, 67, 70, 71, 72, 75, 79, 81, 84, 85, 87, 89, 91, 93, 94, 96, 100, 102, 116, 120, 125, 126, 129, 137, 141, 142, 146, 150, 152, 153, 160, 161, 162, 166, 171, 172, 173, 180
Offset: 1

Views

Author

Bernard Schott, Dec 19 2022

Keywords

Comments

Numbers missing from A358350.
The first differences show some periodicity, for example those for values 2184-3811 repeat at terms 5513-7140. - Bill McEachen, Jan 08 2023

Examples

			There is no term du_10 < 36 such that du + (d+u) + (d*u) = 36, so 36 is a term.
		

Crossrefs

Similar: A003052 (m+digitsum), A230104 (m+digitprod).

Programs

  • Maple
    f:= proc(n) local L; L:= convert(n,base,10); n + convert(L,`+`)+convert(L,`*`) end proc:
    sort(convert({$1..200} minus map(f, {$1..200}),list)); # Robert Israel, Dec 22 2022
  • Mathematica
    f[n_] := n + Total[(d = IntegerDigits[n])] + Times @@ d; With[{m = 180}, Complement[Range[m], Table[f[n], {n, 1, m}]]] (* Amiram Eldar, Dec 19 2022 *)
  • PARI
    f(n) = my(d=digits(n)); vecsum(d)+vecprod(d)+n; \\ A161351
    isok(m) = for(i=1, m, if (f(i) == m, return(0))); return(1); \\ Michel Marcus, Jan 09 2023
  • Python
    from math import prod
    def sp(n): d = list(map(int, str(n))); return sum(d) + prod(d)
    def ok(n): return all(m + sp(m) != n for m in range(n+1))
    print([k for k in range(181) if ok(k)]) # Michael S. Branicky, Dec 19 2022
    
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