

A355200


Numbers k that can be written as the sum of 3 divisors of k (not necessarily distinct).


9



3, 4, 6, 8, 9, 12, 15, 16, 18, 20, 21, 24, 27, 28, 30, 32, 33, 36, 39, 40, 42, 44, 45, 48, 51, 52, 54, 56, 57, 60, 63, 64, 66, 68, 69, 72, 75, 76, 78, 80, 81, 84, 87, 88, 90, 92, 93, 96, 99, 100, 102, 104, 105, 108, 111, 112, 114, 116, 117, 120, 123, 124, 126, 128, 129, 132, 135
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..67.


FORMULA

a(n + 6) = a(n) + 12.  David A. Corneth, Oct 08 2022


EXAMPLE

6 is in the sequence since it can be written as the sum of 3 of its (not necessarily distinct) divisors: 6 = 1+2+3 = 2+2+2 with 16, 26, and 36.


MATHEMATICA

q[n_, k_] := AnyTrue[Tuples[Divisors[n], k], Total[#] == n &]; Select[Range[135], q[#, 3] &] (* Amiram Eldar, Aug 21 2022 *)


PROG

(PARI) isok(k) = my(d=divisors(k)); forpart(p=k, if (setintersect(d, Set(p)) == Set(p), return(1)), , [3, 3]); \\ Michel Marcus, Aug 21 2022
(PARI) is(n) = my(v = [3, 4, 6]); sum(i = 1, 3, n%v[i] == 0) > 0 \\ David A. Corneth, Oct 08 2022


CROSSREFS

Cf. A002966, A348536.
Numbers k that can be written as the sum of j divisors of k (not necessarily distinct) for j=1..10: A000027 (j=1), A299174 (j=2), this sequence (j=3), A354591 (j=4), A355641 (j=5), A356609 (j=6), A356635 (j=7), A356657 (j=8), A356659 (j=9), A356660 (j=10).
Sequence in context: A036446 A284469 A059267 * A049433 A250984 A135251
Adjacent sequences: A355197 A355198 A355199 * A355201 A355202 A355203


KEYWORD

nonn,easy


AUTHOR

Wesley Ivan Hurt, Jun 23 2022


STATUS

approved



