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A338467
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a(n+1) = prime(n) + 2*n - a(n). a(1) = 1.
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0
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1, 3, 4, 7, 8, 13, 12, 19, 16, 25, 24, 29, 32, 35, 36, 41, 44, 49, 48, 57, 54, 61, 62, 67, 70, 77, 76, 81, 82, 85, 88, 101, 94, 109, 98, 121, 102, 129, 110, 135, 118, 143, 122, 155, 126, 161, 130, 175, 144, 181, 148, 187, 156, 191, 168, 199, 176, 207, 180, 215
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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a(1) + a(2) - 2*1 = 1st prime; 1 + 3 - 2*1 = 2.
a(13) + a(14) - 2*13 = 13th prime; 32 + 35 - 2*13 = 41.
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MAPLE
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a:= proc(n) option remember; `if`(n=1, 1,
ithprime(n-1)-a(n-1)+2*n-2)
end:
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = Prime[n - 1] + 2*(n - 1) - a[n - 1]; Array[a, 60] (* Amiram Eldar, Feb 01 2021 *)
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PROG
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(Python)
from sympy import prime
S=[1]
nomb=100
for n in range(1, nomb):
derterm=S[-1]
terme= prime(n)-derterm+2*(len(S))
S.append(terme)
print(S)
(PARI) a(n) = if (n==1, 1, prime(n-1) + 2*(n-1) - a(n-1)); \\ Michel Marcus, Jan 31 2021
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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