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.

A374131 Lexicographically earliest infinite sequence such that for all i, j >= 1, a(i) = a(j) => f(i) = f(j), where f(1) = 1, and for n > 1, f(n) = [A083345(n), A374132(n), A374133(n)], where A083345 is the numerator of the fully additive function with a(p) = 1/p, and A374132 and A374133 are the 2- and 3-adic valuations of A276085, which is fully additive with a(p) = p#/p.

Original entry on oeis.org

1, 2, 3, 3, 4, 5, 4, 6, 7, 8, 4, 9, 4, 10, 11, 7, 4, 8, 4, 12, 13, 14, 4, 15, 16, 17, 4, 18, 4, 19, 4, 20, 21, 22, 23, 24, 4, 25, 26, 27, 4, 28, 4, 29, 30, 31, 4, 32, 16, 10, 33, 34, 4, 35, 36, 37, 38, 39, 4, 40, 4, 41, 42, 43, 44, 45, 4, 46, 47, 48, 4, 14, 4, 49, 50, 33, 51, 52, 4, 50, 53, 54, 4, 55, 56, 57, 58, 59, 4, 60, 61, 62, 63, 64, 65, 66, 4, 15, 67, 68
Offset: 1

Views

Author

Antti Karttunen, Jun 30 2024

Keywords

Comments

Restricted growth sequence transform of the function f given in the definition.
For all i, j >= 1:
A305900(i) = A305900(j) => a(i) = a(j),
a(i) = a(j) => A035263(i) = A035263(j),
a(i) = a(j) => A369001(i) = A369001(j),
a(i) = a(j) => A369004(i) = A369004(j),
a(i) = a(j) => A372573(i) = A372573(j),
a(i) = a(j) => A373137(i) = A373137(j),
a(i) = a(j) => A373258(i) = A373258(j),
a(i) = a(j) => A373483(i) = A373483(j).

Crossrefs

Programs

  • PARI
    up_to = 100000;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A083345(n) = { my(f=factor(n)); numerator(vecsum(vector(#f~, i, f[i, 2]/f[i, 1]))); };
    A276085(n) = { my(f=factor(n)); sum(k=1, #f~, f[k, 2]*prod(i=1,primepi(f[k, 1]-1),prime(i))); };
    Aux374131(n) = if(1==n, n, my(u=A276085(n)); [A083345(n), valuation(u, 2), valuation(u, 3)]);
    v374131 = rgs_transform(vector(up_to, n, Aux374131(n)));
    A374131(n) = v374131[n];

A374205 The 5-adic valuation of A328845(n), where A328845 is a Fibonacci-based variant of the arithmetic derivative.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 01 2024

Keywords

Crossrefs

Programs

  • Mathematica
    A374205[n_] := IntegerExponent[n*Total[MapApply[#2*Fibonacci[#]/# &, FactorInteger[n]]], 5];
    Array[A374205, 100, 2] (* Paolo Xausa, Dec 16 2024 *)
  • PARI
    A328845(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]*fibonacci(f[i,1])/f[i, 1]));
    A374205(n) = valuation(A328845(n), 5);

Formula

a(n) = A112765(A328845(n)).

A374213 The 3-adic valuation of A328768(n), where A328768 is the first primorial based variant of the arithmetic derivative.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jun 30 2024

Keywords

Crossrefs

Cf. A007949, A328768, A373991, A373992 (after its two initial terms, gives the indices of nonzero terms in this sequence).
Cf. also A374133, A374212.

Programs

  • PARI
    A002110(n) = prod(i=1,n,prime(i));
    A328768(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]*A002110(primepi(f[i,1])-1)/f[i, 1]));
    A374213(n) = valuation(A328768(n), 3);

Formula

a(n) = A007949(A328768(n)).

A374132 The 2-adic valuation of A276085(n), where A276085 is the primorial base log-function.

Original entry on oeis.org

0, 1, 1, 1, 0, 1, 0, 2, 0, 1, 2, 1, 0, 3, 2, 1, 0, 1, 3, 5, 0, 1, 0, 2, 0, 1, 5, 1, 0, 1, 0, 2, 0, 2, 1, 1, 0, 3, 0, 1, 0, 1, 2, 1, 0, 1, 1, 2, 0, 4, 3, 1, 0, 3, 0, 4, 0, 1, 1, 1, 0, 1, 1, 2, 0, 1, 4, 2, 0, 1, 0, 1, 0, 1, 4, 4, 0, 1, 1, 3, 0, 1, 1, 2, 0, 3, 0, 1, 0, 2, 2, 4, 0, 2, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 3
Offset: 2

Views

Author

Antti Karttunen, Jun 30 2024

Keywords

Crossrefs

Cf. A036554 (indices of 0's), A003159 (of nonzero terms), A373142 (of 1's), A373267 (of 2's), A369002 (of terms >= 2), A373138 (of terms >= 3).
Cf. also A374133.

Programs

  • PARI
    A276085(n) = { my(f=factor(n)); sum(k=1, #f~, f[k, 2]*prod(i=1,primepi(f[k, 1]-1),prime(i))); };
    A374132(n) = valuation(A276085(n),2);

Formula

a(n) = A007814(A276085(n)).

A374207 The 3-adic valuation of A113177(n), where A113177 is fully additive with a(p) = Fibonacci(p).

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 01 2024

Keywords

Crossrefs

Cf. A007949, A113177, A374051, A374052 (indices of nonzero terms).

Programs

  • PARI
    A113177(n) = if(n<=1, 0, my(f=factor(n)); sum(i=1, #f~, f[i, 2]*fibonacci(f[i,1])));
    A374207(n) = valuation(A113177(n), 3);

Formula

a(n) = A007949(A113177(n)).

A374203 The 3-adic valuation of A328845(n), where A328845 is a Fibonacci-based variant of the arithmetic derivative.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jul 01 2024

Keywords

Crossrefs

Cf. A007949, A328845, A374121, A374122 (after its 2 initial terms, gives the indices of nonzero terms in this sequence).

Programs

  • Mathematica
    A374203[n_] := IntegerExponent[n*Total[MapApply[#2*Fibonacci[#]/# &, FactorInteger[n]]], 3];
    Array[A374203, 100, 2] (* Paolo Xausa, Dec 16 2024 *)
  • PARI
    A328845(n) = if(n<=1, 0, my(f=factor(n)); n*sum(i=1, #f~, f[i, 2]*fibonacci(f[i,1])/f[i, 1]));
    A374203(n) = valuation(A328845(n), 3);

Formula

a(n) = A007949(A328845(n)).
Showing 1-6 of 6 results.