A100957 -id:A100957 - cp's OEIS frontend

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

Robert G. Wilson v, Nov 23 2004

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

Cf. A100026, A100956, A100957.

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}]

A100956 Consider all (2n+1)-digit palindromic primes of the form 70...0M0...07 (so that M is a palindrome with <= 2n-1 digits); a(n) = smallest such M.

Original entry on oeis.org

2, 2, 141, 2, 545, 5, 141, 282, 111, 3, 141, 5, 131, 282, 141, 141, 9, 3, 2, 303, 171, 6, 222, 323, 2, 393, 797, 606, 191, 404, 414, 363, 797, 171, 474, 737, 25752, 545, 20502, 14241, 848, 12821, 15951, 474, 575, 12321, 2, 17771, 8, 666, 14541, 15651, 171, 191

Offset: 1

Robert G. Wilson v, Nov 23 2004

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

Cf. A100026, A100955, A100957.

f[n_] := Block[{k = 0, t = Flatten[ Join[{7}, 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, 55}]

cp's OEIS Frontend

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.

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