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Search: id:A100956
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| A100956 |
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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. |
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3
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| 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
(list; graph; listen)
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OFFSET
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1,1
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MATHEMATICA
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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}]
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CROSSREFS
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Cf. A100026, A100955, A100957.
Sequence in context: A055470 A156524 A003110 this_sequence A078241 A068103 A119512
Adjacent sequences: A100953 A100954 A100955 this_sequence A100957 A100958 A100959
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KEYWORD
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base,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 23 2004
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