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.

A246351 Numbers k such that A048673(k) < k.

Original entry on oeis.org

5, 7, 11, 13, 17, 19, 22, 23, 29, 31, 34, 37, 38, 41, 43, 46, 47, 51, 53, 55, 58, 59, 61, 62, 65, 67, 71, 73, 74, 77, 79, 82, 83, 85, 86, 87, 89, 94, 95, 97, 101, 103, 106, 107, 109, 111, 113, 115, 118, 119, 121, 122, 123, 127, 129, 131, 133, 134, 137, 139, 141, 142, 143, 145, 146, 149, 151, 155, 157, 158, 159
Offset: 1

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Author

Antti Karttunen, Aug 24 2014

Keywords

Comments

The growth rate of the sequence seems to converge:
a(100) = 217
a(1000) = 2231
a(10000) = 21535
a(100000) = 214647
a(1000000) = 2155903
a(10000000) = 21553153
Please see comments in A246282.

Crossrefs

Complement: A246352.
Setwise difference of A246281 and A048674.

Programs

  • PARI
    default(primelimit, 2^22);
    A003961(n) = my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); \\ From Michel Marcus
    A048673(n) = (A003961(n)+1)/2;
    isA246351(n) = (A048673(n) < n);
    n = 0; i = 0; while(i < 10000, n++; if(isA246351(n), i++; write("b246351.txt", i, " ", n)));
    
  • Scheme
    ;; With Antti Karttunen's IntSeq-library.
    (define A246351 (MATCHING-POS 1 1 (lambda (n) (< (A048673 n) n))))