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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A322406 a(n) = n + n*n^n.

Original entry on oeis.org

2, 10, 84, 1028, 15630, 279942, 5764808, 134217736, 3486784410, 100000000010, 3138428376732, 106993205379084, 3937376385699302, 155568095557812238, 6568408355712890640, 295147905179352825872, 14063084452067724991026, 708235345355337676357650, 37589973457545958193355620
Offset: 1

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Author

Ivan Stoykov, Dec 07 2018

Keywords

Comments

All terms are produced by successively applying the three basic operations: exponentiation, multiplication and addition.

Examples

			a(3) = 3 + 3*3^3 = 3 + 3*27 = 8 + 81 = 84.
		

Crossrefs

Equals 2 * A108398.

Programs

Formula

E.g.f.: exp(x) * x - LambertW(-x)/(1 + LambertW(-x))^3. - Vaclav Kotesovec, Dec 20 2018

Extensions

a(12)-a(19) from Stefano Spezia, Dec 07 2018

A374964 a(n) is the smallest positive k such that -n^n == n (mod n + k).

Original entry on oeis.org

1, 1, 2, 1, 5, 1, 3, 1, 9, 1, 11, 1, 13, 1, 14, 1, 17, 1, 7, 1, 21, 1, 23, 1, 25, 1, 3, 1, 29, 1, 6, 1, 33, 1, 35, 1, 37, 1, 39, 1, 41, 1, 7, 1, 45, 1, 18, 1, 49, 1, 50, 1, 53, 1, 19, 1, 45, 1, 59, 1, 61, 1, 7, 1, 65, 1, 63, 1, 44, 1, 71, 1, 40, 1, 12, 1, 12, 1, 27, 1, 81, 1, 23, 1, 85, 1, 58, 1, 8, 1, 6, 1, 9
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Jul 25 2024

Keywords

Crossrefs

Cf. A066068 (n^n+n).

Programs

  • Maple
    f:= proc(n) local k;
      for k from 1 do if n &^ n + n mod (n+k) = 0 then return k fi od
    end proc:
    map(f, [$1..100]); # Robert Israel, Jul 30 2024
  • Mathematica
    a[n_] := Module[{k = 1}, While[PowerMod[n, n, n + k] != k, k++]; k]; Array[a, 100] (* Amiram Eldar, Jul 26 2024 *)
  • PARI
    a(n) = my(k=1); while (-Mod(n, n+k)^n != n, k++); k; \\ Michel Marcus, Jul 26 2024
  • Python
    def a(n): return next(k for k in range(1, n+1) if pow(n, n, n+k) == k)
    print([a(n) for n in range(1, 94)]) # Michael S. Branicky, Jul 26 2024
    
  • Python
    from itertools import count
    def A374964(n):
        m = n**n+n
        return next(d for d in count(1) if not m%(n+d)) # Chai Wah Wu, Aug 12 2024
    

Formula

a(n) = 1 for n even and a(n) <= n for n odd. - Michael S. Branicky, Jul 28 2024
a(n) + n is the least divisor > n of n^n + n. - Robert Israel, Jul 30 2024
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