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 A248150 Numbers whose sum of divisors (A000203) is divisible by 4. 6
 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 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

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Last modified May 19 10:36 EDT 2019. Contains 323390 sequences. (Running on oeis4.)