A114565 Dropping first and last digit of n leaves its largest prime factor.

128, 150, 175, 250, 378, 432, 450, 672, 750, 875, 1024, 1197, 1537, 1593, 1675, 2112, 2176, 2596, 3179, 3192, 3478, 3792, 3977, 4050, 4199, 4232, 4895, 5412, 5612, 6171, 6794, 7738, 8294, 8533, 9072, 9196, 9796, 10614, 10731, 11371, 11398

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Example

Dropping first and last digit of 4199 leaves 19, which is the largest prime factor of 4199=13*17*19.

Mathematica

Select[Range[100, 50000], (First@Last@FactorInteger@# == FromDigits@Rest@Most@IntegerDigits@#) &]

Crossrefs

Sequence in context: A097758 A257446 A130445 * A243812 A194766 A257211

Adjacent sequences: A114562 A114563 A114564 * A114566 A114567 A114568

Keyword

base,easy,nonn

Author

Giovanni Resta, Feb 15 2006

Status

approved