A260416 The smallest prime that is greater than prime(n) and congruent to n mod prime(n).

3, 5, 13, 11, 71, 19, 41, 103, 101, 97, 73, 197, 587, 229, 109, 281, 607, 79, 421, 233, 167, 101, 521, 113, 607, 127, 233, 349, 683, 821, 1301, 163, 307, 173, 631, 1093, 1607, 853, 373, 1597, 757, 223, 1571, 1009, 439, 643, 2579, 271, 503, 2111, 983, 769, 1499, 1811, 569, 2423, 3823, 3581, 613, 2027, 1193, 941, 677, 997

Offset

1,1

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Example

Prime(4)=7, and the smallest prime that is greater than 7 and congruent to 4 mod 7 is 11, so a(4)=11.

Mathematica

lst={}; Do[w=1; Label[begin];
If[PrimeQ[w*Prime[n]+n], AppendTo[lst, w*Prime[n]+n], w=w+1; Goto[begin]], {n, 100}]; lst

Prog

(PARI) first(m)={my(v=vector(m), t, p); for(i=1, m, t=i; while(1, p=prime(t); if((p-i)%prime(i)==0, v[i]=p; break, t++); )); v; } /* Anders Hellström, Aug 11 2015 */
(Haskell)
a260416 n = a260416_list !! (n-1)
a260416_list = f 1 a000040_list where
   f x (p:ps) = g ps where
       g (q:qs) = if (q - x) `mod` p == 0 then q : f (x + 1) ps else g qs
-- Reinhard Zumkeller, Aug 20 2015

Crossrefs

Cf. A000040, A186102.

Sequence in context: A369901 A171424 A231897 * A328380 A256222 A258976

Adjacent sequences: A260413 A260414 A260415 * A260417 A260418 A260419

Keyword

nonn

Author

Ivan N. Ianakiev, Jul 25 2015

Status

approved