A100955 Consider all (2n+1)-digit palindromic primes of the form 30...0M0...03 (so that M is a palindrome with <= 2n-1 digits); a(n) = smallest such M.

1, 1, 1, 2, 5, 2, 2, 8, 5, 434, 5, 313, 272, 838, 5, 272, 8, 505, 1, 7, 212, 7, 151, 686, 2, 242, 656, 656, 323, 929, 121, 242, 262, 12521, 454, 949, 353, 2, 16361, 707, 10301, 515, 29092, 454, 13331, 686, 848, 20602, 1, 484, 737, 101, 242, 121, 15551, 656, 232

Offset

1,4

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Mathematica

f[n_] := Block[{k = 0, t = Flatten[ Join[{3}, Table[0, {n - 1}]]]}, While[s = Drop[t, Min[ -Floor[ Log[10, k]/2], 0]]; k != FromDigits[ Reverse[ IntegerDigits[k]]] || !PrimeQ[ FromDigits[ Join[s, IntegerDigits[k], Reverse[s]]]], k++ ]; k]; Table[ f[n], {n, 57}]

Crossrefs

Cf. A100026, A100956, A100957.

Sequence in context: A065267 A273990 A216022 * A049413 A300691 A102707

Adjacent sequences: A100952 A100953 A100954 * A100956 A100957 A100958

Keyword

base,nonn

Author

Robert G. Wilson v, Nov 23 2004

Status

approved