login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A230045 Palindromic primes with strictly increasing sum of digits. 1
2, 3, 5, 7, 181, 191, 373, 383, 727, 757, 787, 797, 17971, 19891, 19991, 76667, 77977, 78887, 79997, 1987891, 1988891, 1998991, 3799973, 3899983, 3998993, 7897987, 7996997, 9888889, 9889889, 9989899, 199999991, 768989867, 779969977, 779999977, 798989897 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(1)=2; a(n+1) is the smallest palindromic prime with sum of digits > sum of digits of a(n).

LINKS

Shyam Sunder Gupta, Table of n, a(n) for n = 1..63

EXAMPLE

a(6) = 191, sum of digits is 11; a(7) = 373, sum of digits is 13 and 13 > 11.

MATHEMATICA

a = {}; t = 0; Do[z = n*10^(IntegerLength[n] - 1) + FromDigits@Rest@Reverse@IntegerDigits[n]; If[PrimeQ[z], s = Apply[Plus, IntegerDigits[z]]; If[s > t, t = s; AppendTo[a, z]]], {n, 10^5}]; a

CROSSREFS

Cf. A002385, A061248.

Sequence in context: A064155 A230047 A230042 * A069803 A083184 A046478

Adjacent sequences:  A230042 A230043 A230044 * A230046 A230047 A230048

KEYWORD

nonn,base

AUTHOR

Shyam Sunder Gupta, Oct 06 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 21 12:58 EST 2022. Contains 350477 sequences. (Running on oeis4.)