This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A139749 #15 Aug 14 2019 13:31:20 %S A139749 2,3,5,7,11,12,14,16,21,23,27,29,32,34,38,41,43,47,54,56,61,65,67,74, %T A139749 83,87,89,92,98,101,102,104,106,110,111,113,115,119,120,122,126,128, %U A139749 131,133,137,139,140,142,146,153,155,160,164,166,173,179,182,186,188,191 %N A139749 Numbers n such that d_1^r + ... + d_r^1 is a prime number, where d_i are the digits of n (n = d_1, ..., d_r). %H A139749 Harvey P. Dale, <a href="/A139749/b139749.txt">Table of n, a(n) for n = 1..1000</a> %e A139749 1^3 + 3^2 + 7^1 = 17 is prime. Thus 137 is a member of this sequence. - _Derek Orr_, Jul 13 2014 %t A139749 Select[Range[200],PrimeQ[Total[IntegerDigits[#]^Range[IntegerLength[#],1,-1]]]&] (* _Harvey P. Dale_, Aug 14 2019 *) %o A139749 (PARI) for(n=1,10^3,d=digits(n);s=sum(i=1,#d,d[i]^(#d-i+1));if(isprime(s),print1(n,", "))) \\ _Derek Orr_, Jul 13 2014 %Y A139749 Cf. A139751. %K A139749 base,easy,nonn,less %O A139749 1,1 %A A139749 _Ctibor O. Zizka_, May 19 2008 %E A139749 Edited and extended by _Klaus Brockhaus_, May 21 2008