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.

Previous Showing 11-12 of 12 results.

A334859 a(n) = A243071(A225546(n)).

Original entry on oeis.org

0, 1, 2, 3, 8, 4, 128, 6, 5, 16, 32768, 12, 2147483648, 256, 32, 7, 9223372036854775808, 10, 170141183460469231731687303715884105728, 48, 512, 65536, 57896044618658097711785492504343953926634992332820282019728792003956564819968, 24, 17, 4294967296, 20, 768
Offset: 1

Views

Author

Antti Karttunen, Jun 08 2020

Keywords

Crossrefs

Inverse permutation of A334860. Composition of permutations A225546 and A243071, and also of A054429 and A334865.

Formula

a(n) = A243071(A225546(n)).
a(n) = A054429(A334865(n)).
For n >= 1, A000120(a(n)) = A299090(n).
For n > 1, A070939(a(n)) = A334871(n).

A375430 The maximum exponent in the unique factorization of n in terms of distinct terms of A115975 using the dual Zeckendorf representation of the exponents in the prime factorization of n; a(1) = 0.

Original entry on oeis.org

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

Views

Author

Amiram Eldar, Aug 15 2024

Keywords

Comments

First differs from A299090 at n = 128. Differs from A046951 and A159631 at n = 1, 36, 64, 72, ... .
When the exponents in the prime factorization of n are expanded as sums of distinct Fibonacci numbers using the dual Zeckendorf representation (A104326), we get a unique factorization of n in terms of distinct terms of A115975, i.e., n is represented as a product of prime powers (A246655) whose exponents are Fibonacci numbers. a(n) is the maximum exponent of these prime powers. Thus all the terms are Fibonacci numbers.

Examples

			For n = 8 = 2^3, the dual Zeckendorf representation of 3 is 11, i.e., 3 = Fibonacci(2) + Fibonacci(3) = 1 + 2. Therefore 8 = 2^(1+2) = 2^1 * 2^2, and a(8) = 2.
		

Crossrefs

Programs

  • Mathematica
    A130312[n_] := Module[{k = 0}, While[Fibonacci[k] <= n, k++]; Fibonacci[k-2]]; a[n_] := A130312[1 + Max[FactorInteger[n][[;;, 2]]]]; a[1] = 0; Array[a, 100]
  • PARI
    A130312(n) = {my(k = 0); while(fibonacci(k) <= n, k++); fibonacci(k-2);}
    a(n) = if(n == 1, 0, A130312(1 + vecmax(factor(n)[,2])));

Formula

a(n) = A130312(1 + A051903(n)).
a(n) = A000045(A375431(n)).
Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = 1 + Sum_{k>=4} Fibonacci(k) * (1 - 1/zeta(Fibonacci(k)-1)) = 1.48543763231328442311... .
Previous Showing 11-12 of 12 results.