a(n) >= a(n-1) and sum of first n terms is prime

Neil Fernandez primeness at borve.demon.co.uk
Thu Dec 19 05:35:47 CET 2002


2, 3, 6, 6, 6, 6, 8, 10, 12, 12, 12, 14, 16, 18, 18, 18, 24, 32, 34, 36,
38, 42, 46, 48, 54, 56, 64, 68, 78, 90, 90, 94, 102, 114, 122, 124, 134,
144, 148, 150, 152, 160, 168, 170, 178, 182, 190, 192, 200, 216, 220,
222, 234, 234, 234, 246, 260, 264, 268, 270, 278, 280, 290, 292, 294,
294, 300, 302, 310, 312, 312, 318, 318, 330, 348, 350, 370, 380, 384,
388, 408, 410, 424, 428, 444, 450, 450

a(n) = smallest integer greater or equal to a(n-1) such that the sum of
the first n terms is prime

First numbers to appear once, twice, three times, etc. are 2, 6, 6, 6, ?

(See also Felice Russo's sequence A051935, where a(n) must be strictly
greater than a(n-1)).

Neil
-- 
Neil Fernandez





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