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A087544
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a(0) = 1, a(1) = 3, a(n) = smallest prime beginning with the sum of two previous terms.
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4
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1, 3, 41, 443, 48407, 488503, 5369101, 585760421, 59112952201, 5969871262259, 60289842144607, 6625971340686661, 66862611828312689, 7348858316899935071, 741572092872824776001, 7489209511897247110721, 82307816047700718867221
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OFFSET
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0,2
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LINKS
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EXAMPLE
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a(3) = 41, a(4) = 443, a(5) = 48407 is the smallest prime beginning with 41+443=484.
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MAPLE
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A[0]:= 1: A[1]:= 3:
for n from 2 to 20 do
s:= A[n-2]+A[n-1];
for d from 1 do
p:= nextprime(10^d*s);
if floor(p/10^d)=s then A[n]:= p; break fi
od
od:
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MATHEMATICA
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a[0] = 1; a[1] = 3; a[n_] := a[n] = Module[{s = a[n - 1] + a[n - 2]}, Do[p = 10^d*s; While[! PrimeQ[p], p = NextPrime[p]]; If[Floor[p/10^d] == s, Break[]], {d, 1, 20}]; p]; Array[a, 10, 0] (* Amiram Eldar, Dec 10 2018 from the Maple code *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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