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A048977 Primes arising in A048969. 0
3, 7, 13, 19, 31, 61, 127, 127, 331, 307, 307, 631, 1801, 1723, 3169, 1093, 1723, 3571, 1093, 3221, 5419, 3541, 3541, 8269, 5113, 5113, 13267, 8011, 8011, 16651, 10303, 19441, 10303 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..33.

MATHEMATICA

p[n_]:=Module[{c=DivisorSigma[1, n]/DivisorSigma[0, n]}, If[PrimeQ[c], c, 0]]; nn=62000; With[{comps=Complement[Range[nn], Prime[Range[PrimePi[nn]]]]}, Select[ p/@comps, #!=0&]] (* Harvey P. Dale, Feb 19 2012 *)

CROSSREFS

Sequence in context: A023217 A106077 A216515 * A216518 A342822 A154650

Adjacent sequences:  A048974 A048975 A048976 * A048978 A048979 A048980

KEYWORD

nonn

AUTHOR

G. L. Honaker, Jr.

EXTENSIONS

More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jun 17 2001

STATUS

approved

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Last modified June 20 23:20 EDT 2021. Contains 345311 sequences. (Running on oeis4.)