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A362267
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For n >= 0, a(n) is the least integer i >= 0 such that n + p_1 + ... + p_i = q, q prime number, or a(n) = -1 if no such i exists. Here p_1 is the least prime >= n, p_1 < p_2 < ... < p_i are prime numbers (A000040).
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0
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1, 1, 0, 0, 15, 0, 1, 0, 1, 12, 13, 0, 3, 0, 1, 4, 29, 1, 1, 0, 1, 2, 25, 0, 1, 4, 7, 8, 13, 0, 1, 0, 7, 6, 1, 2, 1, 0, 1, 4, 21, 0, 7, 0, 5, 10, 19, 0, 1, 6, 1, 2, 85, 0, 1, 4, 17, 6, 5, 0, 11, 0, 15, 4, 1, 20, 3, 0, 1, 14, 3, 0, 3, 0, 5, 22, 17, 2, 1, 0, 1, 6, 11, 0
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OFFSET
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0,5
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LINKS
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FORMULA
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a(p) = 0 for p prime number.
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EXAMPLE
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n = 4: p_1 >= 4 is 5, a(4) = 4 + p_1 + ... + p_i = 4 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 = 439 which is a prime number, thus a(4) = 15.
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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