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.

A326952 a(n) = A001222(A028905(n)).

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 1, 2, 1, 4, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 4, 1, 1, 1, 2, 2, 1, 1, 1, 5, 1, 1, 1, 1, 1, 3, 3, 1, 3, 1, 1, 1, 7, 3, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 3, 1, 1, 2, 2, 1, 3, 2, 2, 1, 4, 1, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 3, 2, 2
Offset: 1

Views

Author

Joshua Michael McAteer, Aug 06 2019

Keywords

Comments

Multiplicity of prime divisors of n, where n is a number composed of the sorted digits of a prime number.
Conjecture: the sum of the first n terms of A326952 (smallest to largest sorting) is <= the sum of the first n terms of A326953 (largest to smallest sorting). This is true for the first 9592 terms.

Examples

			The 13th prime number is 41. Sorting the digits gives 14. 14 has 2 factors, 2 and 7. The 13th term of this sequence is 2.
		

Crossrefs

Cf. A001222 (bigomega), A028905, A326953 (for reverse sorting).

Programs

  • MATLAB
    nmax= 100;
    p = primes(nmax);
    lp = length(p);
    sfac = zeros(1,lp);
    for i = 1:lp
    digp=str2double(regexp(num2str(p(i)),'\d','match'));
    sdigp = sort(digp);
    l=length(digp);
    conv = 10.^flip(0:(l-1));
    snum = sum(conv.*sdigp);
    sfac(i) = numel(factor(snum));
    end