cp's OEIS Frontend

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.

A090180 Primes p = prime(n) such that p + sum-of-digits(p) +- 1 = prime(n+1).

Original entry on oeis.org

2, 3, 23, 61, 131, 151, 331, 601, 661, 1013, 1033, 1103, 1123, 1231, 1237, 1259, 1307, 1321, 1811, 2131, 2621, 2861, 3301, 4021, 4159, 4373, 4463, 4733, 4759, 4801, 5059, 5101, 6151, 6229, 6397, 6737, 7079, 7369, 7433, 8191, 9109, 10181, 10691, 11119
Offset: 1

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Author

Enoch Haga, Jan 19 2004

Keywords

Examples

			a(2)=23. S(d)=5. 23+5=28. 28+1=29, the next prime in sequence. a(3)=61. S(d)=7. 61+7=68. 68-1=67, the next prime in sequence.
		

Crossrefs

Cf. A089323.

Programs

  • Mathematica
    ppQ[n_]:=Module[{sidn=Total[IntegerDigits[n[[1]]]]},n[[1]]+sidn+1 == n[[2]]||n[[1]]+sidn-1==n[[2]]]; Transpose[Select[Partition[Prime[ Range[1500]],2,1],ppQ]][[1]] (* Harvey P. Dale, Mar 19 2012 *)