This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A131101 #11 Sep 04 2024 19:35:47 %S A131101 1,2,3,5,11,23,27,29,30,32,36,41,53,60,66,75,78,83,89,113,114,117,130, %T A131101 131,132,138,140,171,173,175,179,186,191,204,220,233,239,240,246,251, %U A131101 255,258,260,276,279,281,285,286,293,308,310,325,338,340,354,359,363 %N A131101 Numbers that when added it to their prime factors +1 the result is a prime number, member of A131102. %C A131101 The Sophie Germain prime numbers (A005384) are part of this sequence because when adding to one of them its only prime factor (itself) + 1 = 2*A005384 + 1 the result is another prime number (A005385) %C A131101 Prime factors taken with multiplicity. - _Harvey P. Dale_, Sep 04 2024 %H A131101 Harvey P. Dale, <a href="/A131101/b131101.txt">Table of n, a(n) for n = 1..1000</a> %F A131101 a(n)+ prime factors of a(n) + 1 = p ; p is a prime number, member of A131102. %e A131101 a(8)=29 because 29 + its only prime factor (itself) + 1 = 29+29+1= 59, and 59 is a prime number = A131102(8) = A005385(6). %e A131101 a(9)=30 because 30 + its prime factors + 1 = 30 +(2+3+5)+1 =41, and 41 is a prime number = A131102(9). %t A131101 Select[Range[400],PrimeQ[Total[Times@@@FactorInteger[#]]+#+1]&] (* _Harvey P. Dale_, Sep 04 2024 *) %K A131101 easy,nonn %O A131101 1,2 %A A131101 _Tomas Xordan_, Jun 14 2007