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A123928
Numbers n such that the sum of the first n primes with the final digit 1 is prime (the number of consecutive prime numbers in A030430 that should be added to obtain A129077(x)).
1
1, 3, 11, 27, 29, 31, 33, 49, 73, 77, 79, 123, 149, 157, 167, 169, 189, 207, 211, 219, 223, 227, 241, 261, 313, 319, 323, 329, 333, 357, 359, 417, 419, 423, 441, 463, 477, 491, 499, 513, 517, 553, 559, 573, 637, 667, 707, 709, 711, 729, 747, 757, 777, 813, 893
OFFSET
1,2
LINKS
FORMULA
a(n)=primes in A030430 added to obtain A129077(n)
EXAMPLE
a(3)=11 because 11 is the number of consecutive prime numbers in A030430 that must be added to obtain A129077(3).
MATHEMATICA
Position[Accumulate[Select[Prime[Range[5000]], Mod[#, 10]==1&]], _?PrimeQ]//Flatten (* Harvey P. Dale, May 21 2023 *)
CROSSREFS
KEYWORD
easy,base,nonn,less
AUTHOR
Tomas Xordan, May 13 2007
STATUS
approved