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A172321 Duplicate of A154689. 0
5, 7, 10, 13, 14, 18, 19, 26, 31, 38, 39, 43, 50, 55, 61, 62, 69, 72, 73, 78, 84, 86, 91, 95, 96, 98, 103, 108, 109, 110, 115, 119, 122, 123, 129, 133, 136, 138, 139, 145, 146, 151, 153, 159, 181, 182, 187, 190, 193, 199, 205 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that d(n)=d(n-d(n)).

LINKS

Table of n, a(n) for n=1..51.

MATHEMATICA

sndQ[n_]:=Module[{dn=DivisorSigma[0, n]}, dn==DivisorSigma[0, n-dn]]; Select[ Range[250], sndQ] (* Harvey P. Dale, Mar 05 2014 *)

PROG

(PARI) for(n=3, 1000, if(numdiv(n)==numdiv(n-numdiv(n)), print1(n, ", ")))

CROSSREFS

Sequence in context: A218852 A028810 A097700 * A154689 A175766 A243187

Adjacent sequences:  A172318 A172319 A172320 * A172322 A172323 A172324

KEYWORD

nonn,dead

AUTHOR

Juri-Stepan Gerasimov, Nov 20 2010

STATUS

approved

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Last modified April 18 12:42 EDT 2019. Contains 322209 sequences. (Running on oeis4.)