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.
Table[ Mod[Plus@@Table[Mod[Plus@@IntegerDigits[n,k],k],{k,2,n-1}],n],{n,3,100}]
Table[Sum[Mod[Total[IntegerDigits[n,i]], i], {i,2,n-1}], {n,3,59}] (* Stefano Spezia, Sep 06 2022 *)
a(n) = sum(b=2, n-1, sumdigits(n, b) % b); \\ Michel Marcus, Sep 06 2022
from sympy.ntheory import digits def a(n): return sum(sum(digits(n, b)[1:])%b for b in range(2, n)) print([a(n) for n in range(3, 60)]) # Michael S. Branicky, Sep 06 2022
f:= proc(n) local b; add(convert(convert(n,base,b),`+`), b = select(t -> igcd(t,n)=1, [$2..n-1])) end proc: map(f, [$3..100]); # Robert Israel, Nov 08 2024
Table[Sum[If[CoprimeQ[i, n], Mod[Total[IntegerDigits[n, i]], n], 0], {i, 2, n-1}], {n, 3, 61}] (* Stefano Spezia, Sep 06 2022 *)
a(n) = {s = 0; for (i=2, n-1, if (gcd(i, n) == 1, d = digits(n, i); s += sum(j=1, #d, d[j]););); s;} \\ Michel Marcus, May 30 2014
from math import gcd from sympy.ntheory import digits def a(n): return sum(sum(digits(n, b)[1:]) for b in range(2, n) if gcd(b, n) == 1) print([a(n) for n in range(3, 62)]) # Michael S. Branicky, Sep 06 2022
Table[Sum[If[PrimeQ[i], Mod[Total[IntegerDigits[n, i]], n], 0], {i, 2, n-1}],{n, 3, 63}] (* Stefano Spezia, Sep 06 2022 *)
a(n) = {s = 0; forprime (i=2, n-1, d = digits(n, i); s += sum(j=1, #d, d[j]);); s;} \\ Michel Marcus, May 30 2014
from sympy.ntheory import digits, isprime def a(n): return sum(sum(digits(n, b)[1:]) for b in range(2, n) if isprime(b)) print([a(n) for n in range(3, 64)]) # Michael S. Branicky, Sep 06 2022
Table[Sum[If[PrimePowerQ[i], Mod[Total[IntegerDigits[n, i]], n], 0], {i, 2, n-1}], {n, 3, 60}] (* Stefano Spezia, Sep 06 2022 *)
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