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 A257525 Composite numbers equal to the sum of the prime factors, with multiplicity, of the previous k numbers, for some k. 6
 94, 123, 147, 806, 1081, 1179, 1775, 2575, 5374, 14865, 20490, 20845, 27177, 54934, 72599, 87031, 101827, 391514, 452574, 534389, 1197146, 1219229, 1297767, 1327510, 4565354, 4946164, 6124646, 7967984, 8637602, 9615708, 10061718, 14563178, 18997520, 24277270 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Values of k are 4, 4, 4, 8, 8, 7, 7, 8, 9, 13, 5, 19, 14, 14, 5, 17, 11, 21, 17, 5, 12, 10, 22, 14, 23, 24, 19, 17, 18, 22, 34, 8, 38, 35, ... LINKS Paolo P. Lava, First 50 terms with associated k values EXAMPLE For 94, consider the prime factors of the previous 4 numbers, 90, 91, 92, 93: 2, 3, 3, 5; 7, 13; 2, 2, 23; 3, 31. Their sum is 2 + 3 + 3 + 5 + 7 + 13 + 2 + 2 + 23 + 3 + 31 = 94. For 123, condider the prime factors of the previous 4 numbers, 119, 120, 121, 122: 7, 17; 2, 2, 2, 3, 5; 11, 11; 2, 61. Their sum is 7 + 17 + 2 + 2 + 2 + 3 + 5 + 11 + 11 + 2 + 61 = 123. MAPLE with(numtheory): P:= proc(q) local a, d, j, k, n; for n from 2 to q do if not isprime(n) then a:=0; k:=0; while a

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Last modified May 5 17:02 EDT 2021. Contains 343572 sequences. (Running on oeis4.)