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A260416
The smallest prime that is greater than prime(n) and congruent to n mod prime(n).
3
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
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
Sequence in context: A369901 A171424 A231897 * A328380 A256222 A258976
KEYWORD
nonn
AUTHOR
Ivan N. Ianakiev, Jul 25 2015
STATUS
approved