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A107819
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Slowest increasing sequence where a(n)+n is prime.
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1
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1, 3, 4, 7, 8, 11, 12, 15, 20, 21, 26, 29, 30, 33, 38, 43, 44, 49, 52, 53, 58, 61, 66, 73, 76, 77, 80, 81, 84, 97, 100, 105, 106, 115, 116, 121, 126, 129, 134, 139, 140, 149, 150, 153, 154, 165, 176, 179, 180, 183
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| Appears to be closely related to A014692.
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EXAMPLE
| (1)+1=2, which is prime; (3)+2=5=prime; (4)+3=7=prime; (7)+4=11=prime; (8)+5=13=prime; etc.
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MAPLE
| A107819 := proc(n)
option remember;
if n = 1 then
return 1;
else
for a from procname(n-1)+1 do
if isprime(a+n) then
return a;
end if;
end do:
end if;
end proc: # R. J. Mathar, Sep 05 2011
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PROG
| (Sage)
@cached_function
def A107819(n):
....prev = (-1 if n == 1 else A107819(n-1))
....return next_prime(prev+n)-n # [D. S. McNeil, Sep 05 2011]
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CROSSREFS
| Sequence in context: A028970 A188259 A058235 * A067186 A133675 A173467
Adjacent sequences: A107816 A107817 A107818 * A107820 A107821 A107822
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KEYWORD
| easy,nonn
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AUTHOR
| Eric Angelini (eric.angelini(AT)kntv.be), Jun 11 2005
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EXTENSIONS
| Corrected by R. J. Mathar, Sep 05 2011
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