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 1-1 of 1 results.

A177512 A053735-deficient numbers.

Original entry on oeis.org

1, 2, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251
Offset: 1

Views

Author

Vladimir Shevelev, Dec 11 2010

Keywords

Comments

For definition, see A175522.
All primes, except for 3, are in the sequence.
It also contains squared primes p^2 for p = 5, 7, 11, 13, 19, 23, 29, 31, 37.. (not matching current OEIS sequences). What characterizes these p?

Links

Crossrefs

Cf. A177511 (perfect version), A175524, A175811, A000040, A005100, A005101.

Programs

  • PARI
    isok(n) = sumdiv(n, d, (dMichel Marcus, Feb 06 2016
  • Sage
    is_A177512 = lambda n: sum(A053735(d) for d in divisors(n)) < 2*A053735(n) # D. S. McNeil, Dec 11 2010

Formula

{n: sum_{d|n, dA053735(d) < A053735(n)}.
Showing 1-1 of 1 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.