A283565 Numbers n such that n = Sum_{k=1..m} (n mod k) for some m.

0, 1, 2, 7, 8, 9, 10, 13, 15, 19, 22, 23, 25, 31, 37, 49, 51, 52, 57, 72, 95, 98, 100, 133, 140, 146, 152, 158, 168, 189, 196, 212, 315, 348, 376, 383, 396, 407, 416, 451, 452, 497, 521, 541, 548, 551, 568, 583, 586, 592, 593, 657, 663, 683, 729, 780, 784, 794

Offset

1,3

Comments

A283593 gives the least m > 0 as described in the name.

Numbers t such that t and 2*t are both in this sequence are 0, 1, 49, 98, 1249, 2599, 3784, 9565, 10933, ... - Altug Alkan, Mar 11 2017

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Example

(7 mod 1) + (7 mod 2) + (7 mod 3) + (7 mod 4) + (7 mod 5) = 0 + 1 + 1 + 3 + 2 = 7, hence 7 appears in this sequence.
(4 mod 1) + (4 mod 2) + (4 mod 3) + (4 mod 4) = 0 + 0 + 1 + 0 = 1, and (4 mod 1) + (4 mod 2) + (4 mod 3) + (4 mod 4) + (4 mod 5) = 0 + 0 + 1 + 0 + 4 = 5, hence 4 does not appear in this sequence.

Prog

(PARI) isok(n) = my (s=0); my (k=1); while (s<n, s += n%k; k++); return (s==n)

Crossrefs

Cf. A004125, A283593.

Sequence in context: A253251 A093915 A152769 * A047527 A064517 A270804

Adjacent sequences: A283562 A283563 A283564 * A283566 A283567 A283568

Keyword

nonn

Author

Rémy Sigrist, Mar 11 2017

Status

approved