

A015915


Numbers k such that sigma(k) + 8 = sigma(k+8).


8



3, 5, 11, 23, 27, 29, 53, 59, 71, 89, 101, 131, 149, 173, 191, 233, 263, 269, 359, 389, 401, 431, 449, 479, 491, 563, 569, 593, 599, 653, 683, 701, 719, 743, 761, 821, 911, 929, 983, 1013, 1031, 1061, 1109, 1163, 1193, 1223, 1229, 1283, 1289
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OFFSET

1,1


COMMENTS

Different from A023202. Below 1000000 four composites were found [27, 1615, 1885, 218984] satisfying the "sigma(k) + 8 = sigma(k+8)" relation, together with more than 8000 primes.  Labos Elemer, May 23 2000


LINKS



EXAMPLE

sigma(27) + 8 = 48 = sigma(27+8), so 27 is in the sequence.


MATHEMATICA

Select[Range[1300], DivisorSigma[1, #]+8==DivisorSigma[1, #+8]&] (* Harvey P. Dale, Jul 16 2011 *)


PROG



CROSSREFS

Composite solutions are in A059118.


KEYWORD

nonn


AUTHOR



STATUS

approved



