OFFSET
1,1
COMMENTS
Also, numbers k such that k = antisigma(k) - antisigma(k-1), where antisigma(k) = A024816(k) = the sum of the non-divisors of k that are between 1 and k.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10135 (calculated using the b-file at A002961; terms 1..550 from Hugo Pfoertner)
FORMULA
a(n) = A002961(n) + 1.
EXAMPLE
15 = antisigma(15) - antisigma(14) = 96 - 81.
MATHEMATICA
SequencePosition[DivisorSigma[1, Range[210000]], {x_, x_}][[;; , 2]] (* Harvey P. Dale, May 28 2024 *)
PROG
(PARI) n=0; sp=sigma(2); for(k=3, oo, my(s=sigma(k)); if(s==sp, print1(k, ", "); n++; if(n>36, break)); sp=s) \\ Hugo Pfoertner, Mar 06 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Nov 11 2013
EXTENSIONS
More terms from Hugo Pfoertner, Mar 06 2020
STATUS
approved