The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A248150 Numbers whose sum of divisors (A000203) is divisible by 4. 8
 3, 6, 7, 11, 12, 14, 15, 19, 21, 22, 23, 24, 27, 28, 30, 31, 33, 35, 38, 39, 42, 43, 44, 46, 47, 48, 51, 54, 55, 56, 57, 59, 60, 62, 63, 65, 66, 67, 69, 70, 71, 75, 76, 77, 78, 79, 83, 84, 85, 86, 87, 88, 91, 92, 93, 94, 95, 96, 99, 102, 103, 105, 107, 108, 110, 111, 112, 114, 115, 118 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A subsequence of A028983 (even sum of divisors) which contains all numbers but the squares and twice the squares, so no term of this sequence is of that form, either. Any number having at least two odd prime factors to an odd power is in this sequence, therefore it has asymptotic density 1. - M. F. Hasler, Apr 26 2017 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 FORMULA a(n) ~ n. - Charles R Greathouse IV, Sep 01 2015 MATHEMATICA Select[Range[200], Divisible[DivisorSigma[1, #], 4]&] (* Harvey P. Dale, Feb 20 2015 *) PROG (PARI) for(n=1, 999, sigma(n)%4||print1(n", ")) CROSSREFS Cf. A000203, A028982, A028983, A248151. Sequence in context: A136272 A101184 A087643 * A022544 A194366 A091067 Adjacent sequences:  A248147 A248148 A248149 * A248151 A248152 A248153 KEYWORD nonn AUTHOR M. F. Hasler, Oct 02 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 6 01:16 EDT 2020. Contains 334858 sequences. (Running on oeis4.)