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.

Showing 1-6 of 6 results.

A328114 Maximal digit value used when n is written in primorial base (cf. A049345).

Original entry on oeis.org

0, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3
Offset: 0

Views

Author

Antti Karttunen, Oct 12 2019

Keywords

Examples

			For n = 2105, which could be expressed in primorial base for example as "T0021" (where T here stands for the digit value ten), or maybe more elegantly as [10,0,0,2,1] as 2105 = 10*A002110(4) + 2*A002110(1) + 1*A002110(0). The maximum value of these digits is 10, thus a(2105) = 10.
		

Crossrefs

Programs

  • Mathematica
    With[{b = MixedRadix[Reverse@ Prime@ Range@ 20]}, Array[Max@ IntegerDigits[#, b] &, 105, 0]] (* Michael De Vlieger, Oct 30 2019 *)
  • PARI
    A328114(n) = { my(i=0,m=0,pr=1,nextpr); while((n>0),i=i+1; nextpr = prime(i)*pr; if((n%nextpr),m = max(m,(n%nextpr)/pr); n-=(n%nextpr));pr=nextpr); (m); };
    
  • PARI
    A328114(n) = { my(s=0, p=2); while(n, s = max(s,(n%p)); n = n\p; p = nextprime(1+p)); (s); }; \\ (Faster, no unnecessary construction of primorials) - Antti Karttunen, Oct 29 2019

Formula

a(n) = A051903(A276086(n)).
a(A276156(n)) = 1 for all n >= 1.
a(n) <= A276150(n) for all n >= 0.
From Antti Karttunen, Oct 29 2019: (Start)
a(n) = A061395(A328835(n)).
For n >= 1, a(n) < A000040(A235224(n)) and a(n) <= 1 + A328391(n).
For all n >= 1, a(n) = 1+A051903(A328572(n)).
a(A276086(n)) = A328389(n), a(A276087(n)) = A328394(n), a(A328403(n)) = A328398(n).
a(A327860(n)) = A328392(n), a(A003415(n)) = A328390(n), a(A328316(n)) = A328322(n).
(End)

A328316 Iterates of A276086 starting from 0.

Original entry on oeis.org

0, 1, 2, 3, 6, 5, 18, 125, 43218, 258413198822535882125
Offset: 0

Views

Author

Antti Karttunen, Oct 14 2019

Keywords

Comments

The unique infinite sequence such that a(0) = 0, a(n) = A276085(a(n+1)) for n >= 0, and A129251(a(n)) = 0 for n >= 1, i.e., all nonzero terms must be in A048103.
a(10) is 240 decimal digits long (can be found in b-file), and a(11) is too big to fit even into a b-file as it is 32700 decimal digits long, but it can be found in the given a-file.

Crossrefs

Cf. A002110, A048103, A129251, A276085, A276086, A328317 (the smallest prime not dividing a(n)), A328318, A328319 (digit sum in primorial base), A328322 (max. digit), A328323.
Cf. A153013, and also A109162, A179016, A219666, A259934 for more or less analogous sequences.
Cf. also A328313.

Programs

Formula

a(0) = 0; and for n > 0, a(n) = A276086(a(n-1)).

A328389 Maximal digit value in primorial base expansion of A276086(n): a(n) = A328114(A276086(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 3, 2, 2, 2, 1, 2, 3, 4, 3, 2, 5, 2, 2, 4, 2, 5, 4, 5, 10, 6, 6, 8, 6, 5, 9, 1, 2, 3, 2, 2, 4, 2, 2, 3, 1, 3, 3, 5, 4, 3, 5, 7, 4, 4, 8, 3, 3, 4, 9, 9, 8, 7, 11, 4, 8, 3, 3, 4, 4, 3, 4, 2, 2, 3, 7, 10, 10, 5, 4, 6, 3, 8, 9, 7, 5, 10, 10, 10, 8, 5, 5, 8, 6, 9, 7, 4, 4, 6, 9, 4, 7, 8, 5, 3, 5, 7, 4, 7, 7, 11, 9
Offset: 0

Views

Author

Antti Karttunen, Oct 15 2019

Keywords

Crossrefs

Programs

  • PARI
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A328114(n) = { my(s=0, p=2); while(n, s = max(s,(n%p)); n = n\p; p = nextprime(1+p)); (s); };
    A328389(n) = A328114(A276086(n));

Formula

a(n) = A328114(A276086(n)).
a(n) = A051903(A276087(n)).

A328317 Smallest prime not dividing A328316(n), with a(0) = 1 by convention; Equally, for n > 0, smallest prime dividing A328316(1+n).

Original entry on oeis.org

1, 2, 3, 2, 5, 2, 5, 2, 5, 2, 5, 2, 5, 2
Offset: 0

Views

Author

Antti Karttunen, Oct 14 2019

Keywords

Comments

a(2n+1) = 2 for all n >= 0. Does the pattern of 5's in the even bisection also continue?

Crossrefs

Programs

Formula

a(0) = 1; and for n > 0, a(n) = A053669(A328316(n)).
a(n) = A020639(A328316(1+n)).
For n >= 1, a(n) = A326810(A328316(n-1)). - Antti Karttunen, Nov 15 2019

Extensions

a(12)-a(13) from Jinyuan Wang, Jul 20 2020

A328394 Maximal digit value in primorial base expansion of A276087(n): a(n) = A328114(A276087(n)).

Original entry on oeis.org

1, 1, 1, 2, 1, 4, 3, 2, 5, 1, 5, 4, 6, 3, 3, 7, 7, 4, 7, 5, 16, 6, 12, 27, 21, 35, 28, 23, 31, 28, 2, 2, 4, 5, 4, 5, 4, 10, 9, 2, 11, 6, 7, 10, 12, 7, 30, 6, 10, 15, 14, 7, 23, 37, 26, 32, 28, 33, 24, 28, 8, 3, 17, 11, 3, 5, 6, 11, 7, 12, 30, 21, 28, 15, 28, 11, 24, 30, 14, 16, 43, 17, 52, 26, 19, 29, 27, 33, 46, 27, 12, 15, 28, 28, 24, 27, 11, 20, 16, 20
Offset: 0

Views

Author

Antti Karttunen, Oct 15 2019

Keywords

Crossrefs

Programs

  • Mathematica
    Block[{b = MixedRadix[Reverse@ Prime@ Range@ 120], f}, f[n_] := Times @@ Power @@@ # &@ Transpose@ {Prime@ Range@ Length@ #, Reverse@ #} &@ IntegerDigits[n, b]; Array[Max@ IntegerDigits[Nest[f, #, 2], b] &, 100, 0]] (* Michael De Vlieger, Oct 15 2019 *)
  • PARI
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A276087(n) = A276086(A276086(n));
    A328114(n) = { my(s=0, p=2); while(n, s = max(s,(n%p)); n = n\p; p = nextprime(1+p)); (s); };
    A328394(n) = A328114(A276087(n));

Formula

a(n) = A328389(A276086(n)) = A328114(A276087(n)) = A051903(A328403(n)).

A328319 Sum of digits when A328316(n) is written in primorial base; number of prime factors in A328316(1+n), counted with multiplicity.

Original entry on oeis.org

0, 1, 1, 2, 1, 3, 3, 7, 21, 159, 12927, 132571335
Offset: 0

Views

Author

Antti Karttunen, Oct 14 2019

Keywords

Crossrefs

Programs

  • PARI
    A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
    A328316(n) = if(!n,0,A276086(A328316(n-1)));
    A276150(n) = { my(s=0, p=2, d); while(n, d = (n%p); s += d; n = (n-d)/p; p = nextprime(1+p)); (s); };
    A328319(n) = A276150(A328316(n));
    \\ Or alternatively, more slowly as:
    A328319(n) = bigomega(A328316(1+n));

Formula

a(n) = A276150(A328316(n)).
a(n) = A001222(A328316(1+n)).
Showing 1-6 of 6 results.