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.

A324107 Fixed points of A324106, where A324106 is a multiplicative function with A324106(p^e) = A005940(p^e).

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 63, 64, 80, 96, 120, 126, 128, 160, 192, 240, 252, 256, 315, 320, 384, 480, 504, 512, 630, 640, 768, 960, 1008, 1024, 1260, 1280, 1536, 1920, 2016, 2048, 2520, 2560, 3072, 3840, 4032, 4096, 5040, 5120, 6144, 7680, 8064, 8192, 10080, 10240, 12288, 15360, 16128, 16384
Offset: 1

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Author

Antti Karttunen, Feb 15 2019

Keywords

Comments

Numbers n such that A324106(n) = n.

Examples

			For n = 63 = 3^2 * 7^1, we find that A005940(9) = 7 and A005940(7) = 9, thus A324106(63) = 7*9 = 63, and 63 is a member of this sequence.
		

Crossrefs

Cf. A029747 (a subsequence).

Programs

  • PARI
    A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); t }; \\ From A005940
    A324106(n) = { my(f=factor(n)); prod(i=1, #f~, A005940(f[i,1]^f[i,2])); };
    isA324107(n) = (n==A324106(n));
    for(n=1,16384,if(isA324107(n), print1(n,", ")))