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A129747
Numbers n such that the sum of the first n primes with the final digit 7 is prime.
1
1, 3, 7, 9, 11, 17, 31, 43, 63, 77, 81, 101, 109, 111, 117, 123, 127, 137, 147, 149, 153, 157, 161, 167, 171, 193, 199, 231, 233, 241, 243, 281, 311, 317, 321, 327, 329, 347, 367, 393, 421, 433, 439, 443, 483, 499, 531, 587, 591, 611, 619, 621, 623, 679, 683
OFFSET
1,2
LINKS
FORMULA
a(n)=primes in A030432 added to obtain A129079(n)
MATHEMATICA
Position[Accumulate[Select[Prime[Range[3000]], Mod[#, 10]==7&]], _?(PrimeQ[ #]&)]//Flatten (* Harvey P. Dale, Dec 27 2021 *)
CROSSREFS
KEYWORD
easy,base,less,nonn
AUTHOR
Tomas Xordan, May 14 2007
STATUS
approved