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.

A328842 Decrement each nonzero digit by one in primorial base representation of n, then convert back to decimal.

Original entry on oeis.org

0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 2, 6, 6, 6, 6, 8, 8, 12, 12, 12, 12, 14, 14, 18, 18, 18, 18, 20, 20, 0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 2, 6, 6, 6, 6, 8, 8, 12, 12, 12, 12, 14, 14, 18, 18, 18, 18, 20, 20, 30, 30, 30, 30, 32, 32, 30, 30, 30, 30, 32, 32, 36, 36, 36, 36, 38, 38, 42, 42, 42, 42, 44, 44, 48, 48, 48, 48, 50, 50, 60, 60
Offset: 0

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Author

Antti Karttunen, Oct 30 2019

Keywords

Crossrefs

Cf. A276156 (positions of zeros).
Cf. A276009 for analogous sequence.

Programs

  • PARI
    A328842(n) = { my(p=2, r=1, s=0); while(n, if((n%p)>0, s += ((n%p)-1)*r); r *= p; n = n\p; p = nextprime(1+p)); (s); };

Formula

a(n) = n - A328841(n).
For all n >= 0, a(A276086(n)) = A328844(n).
For all n >= 1, A328114(a(n)) = A328114(n) - 1.