OFFSET
1,4
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..15120
Antti Karttunen, Data supplement: n, a(n) computed for n = 1..100000
MATHEMATICA
Array[DivisorSum[2 #, 1 &, And[EvenQ@ #, PrimeQ[# - 1]] &] &, 105] (* Michael De Vlieger, Jan 04 2019 *)
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jan 04 2019
STATUS
approved