|
|
A015913
|
|
Numbers k such that sigma(k) + 4 = sigma(k+4).
|
|
19
|
|
|
3, 7, 13, 19, 37, 43, 67, 79, 97, 103, 109, 127, 163, 193, 223, 229, 277, 307, 313, 349, 379, 397, 439, 457, 463, 487, 499, 613, 643, 673, 739, 757, 769, 823, 853, 859, 877, 883, 907, 937, 967, 1009, 1087, 1093, 1213, 1279, 1297, 1303, 1423
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
This sequence contains the composite number 305635357, so is different from A023200 and A029710 (305635357 is the only composite member of the present sequence below 10^9). - Jud McCranie, Jan 07 2001
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[Range[1500], DivisorSigma[1, #]+4==DivisorSigma[1, #+4]&] (* Harvey P. Dale, Nov 04 2011 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|