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.

A319715 Sum of A276150(d) over divisors d of n, where A276150 gives the sum of digits in primorial base.

Original entry on oeis.org

1, 2, 3, 4, 4, 5, 3, 6, 6, 8, 5, 9, 4, 7, 10, 10, 6, 11, 5, 14, 10, 11, 7, 15, 9, 10, 12, 15, 8, 16, 3, 12, 10, 10, 10, 17, 4, 9, 10, 20, 6, 18, 5, 17, 18, 13, 7, 23, 8, 18, 14, 18, 8, 22, 14, 23, 14, 16, 9, 26, 4, 7, 17, 16, 12, 20, 5, 16, 14, 22, 7, 27, 6, 10, 21, 17, 14, 22, 7, 30, 19, 14, 9, 34, 16, 13, 18, 27, 10, 30, 10, 19, 10
Offset: 1

Views

Author

Antti Karttunen, Oct 02 2018

Keywords

Comments

Inverse Möbius transform of A276150.

Crossrefs

Programs

  • Mathematica
    d[n_] := Module[{k = n, p = 2, s = 0, r}, While[{k, r} = QuotientRemainder[k, p]; k != 0 || r != 0, s += r; p = NextPrime[p]]; s]; a[n_] := DivisorSum[n, d[#] &]; Array[a, 100] (* Amiram Eldar, Mar 05 2024 *)
  • PARI
    A276150(n) = { my(s=0, p=2, d); while(n, d = (n%p); s += d; n = (n-d)/p; p = nextprime(1+p)); (s); };
    A319715(n) = sumdiv(n,d,A276150(d));

Formula

a(n) = Sum_{d|n} A276150(d).
a(n) = A319713(n) + A276150(n).