A066688 Numbers n such that p(n) is congruent to n mod sigma(n), where p(n) denotes the n-th prime.

1, 5, 13, 31, 299, 667, 3805, 15965, 74053, 274483, 10553437, 19329979, 71074261, 179992919, 264401891, 296059565, 8200981757, 22718360827, 24163572401

Offset

1,2

Comments

a(20) > 10^12. [From Donovan Johnson, Mar 14 2010]

Links

Table of n, a(n) for n=1..19.

Example

p(5) = 11 is congruent to 5 mod sigma(5) = 6; so 5 is a term of the sequence.

Mathematica

Select[ Range[ 1, 10^6 ], Mod[ #, DivisorSigma[ 1, # ] ] == Mod[ Prime[ # ], DivisorSigma[ 1, # ] ] & ]
Select[ Range[ 1, 4 10^7 ], # == Mod[ Prime[ # ], DivisorSigma[ 1, # ]] & ]

Crossrefs

Sequence in context: A147424 A146057 A062403 * A046789 A271902 A272539

Adjacent sequences: A066685 A066686 A066687 * A066689 A066690 A066691

Keyword

nonn

Author

Joseph L. Pe, Jan 11 2002

Extensions

More terms from Robert G. Wilson v, Jan 13 2002

a(13)-a(19) from Donovan Johnson, Mar 14 2010

Status

approved