A087544 a(0) = 1, a(1) = 3, a(n) = smallest prime beginning with the sum of two previous terms.

1, 3, 41, 443, 48407, 488503, 5369101, 585760421, 59112952201, 5969871262259, 60289842144607, 6625971340686661, 66862611828312689, 7348858316899935071, 741572092872824776001, 7489209511897247110721, 82307816047700718867221

Offset

0,2

Links

Robert Israel, Table of n, a(n) for n = 0..322

Example

a(3) = 41, a(4) = 443, a(5) = 48407 is the smallest prime beginning with 41+443=484.

Maple

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:
seq(A[n], n=0..20); # Robert Israel, Dec 10 2018

Mathematica

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 *)

Crossrefs

Cf. A087541, A087542, A087543.

Sequence in context: A181226 A159249 A328509 * A305667 A213378 A189356

Adjacent sequences: A087541 A087542 A087543 * A087545 A087546 A087547

Keyword

base,nonn

Author

Amarnath Murthy, Sep 13 2003

Extensions

More terms from Ray Chandler, Sep 23 2003

Status

approved