A239547 a(1) = 1; a(n) is smallest number > a(n-1) such that the juxtaposition a(n)a(n-1)...a(1) is a prime.

1, 3, 4, 5, 7, 14, 21, 43, 56, 96, 141, 178, 180, 198, 263, 271, 315, 347, 352, 471, 530, 565, 588, 707, 711, 793, 812, 850, 887, 952, 1083, 1214, 1218, 1266, 1564, 1661, 1686, 1744, 1976, 2047, 2066, 2166, 2268, 2412, 2740, 2777, 2895, 2905, 3056, 3058, 3293

Offset

1,2

Links

Paolo P. Lava, Table of n, a(n) for n = 1..100

Maple

with(numtheory);
S:=proc(s) local w; w:=convert(s, base, 10); sum(w[j], j=1..nops(w)); end:
T:=proc(t) local w, x, y; x:=t; y:=0; while x>0 do x:=trunc(x/10); y:=y+1; od; end:
P:=proc(q) local a, b, c, j, n; a:=1; j:=2; print(1);
for n from 1 to q do b:=T(a); c:=j*10^b+a;
if isprime(c) then a:=j*10^b+a; print(j); fi;
j:=j+1; od; print(); end: P(10^10);

Crossrefs

Cf. A033680, A074336.

Sequence in context: A101759 A089560 A248077 * A060728 A330712 A295988

Adjacent sequences: A239544 A239545 A239546 * A239548 A239549 A239550

Keyword

nonn,base

Author

Paolo P. Lava, Mar 21 2014

Status

approved