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A172115
Partial sums of A001605 indices of prime Fibonacci numbers.
0
3, 7, 12, 19, 30, 43, 60, 83, 112, 155, 202, 285, 416, 553, 912, 1343, 1776, 2225, 2734, 3303, 3874, 6845, 11568, 16955, 26266, 35943, 50374, 75935, 106692, 142691, 180202, 231035, 312874, 417785, 547806, 695897, 897004, 1294383, 1728164
OFFSET
1,1
COMMENTS
Primes in this sequence include a(1) = 3, a(2) = 7, a(4) = 19, a(6) = 43, a(8) = 83. Because the underlying sequence is hard, so is this, and so it is hard to determine if there is ever another such prime sum of indices of prime Fibonacci numbers.
EXAMPLE
a(20) = 3 + 4 + 5 + 7 + 11 + 13 + 17 + 23 + 29 + 43 + 47 + 83 + 131 + 137 + 359 + 431 + 433 + 449 + 509 + 569 = 3303.
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Jonathan Vos Post, Jan 25 2010
STATUS
approved