A129747 - OEIS

A129747

Numbers n such that the sum of the first n primes with the final digit 7 is prime.

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

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

Cf. A129079; A000040; A030432.

Sequence in context: A287202 A156770 A088630 * A354570 A354039 A004614

Adjacent sequences: A129744 A129745 A129746 * A129748 A129749 A129750

KEYWORD

easy,base,less,nonn

AUTHOR

Tomas Xordan, May 14 2007

STATUS

approved