

A278702


Table T(n, k) read by antidiagonals: maximal length of arithmetic progression of primes starting at prime(n) and with common difference 2*k.


0



3, 3, 2, 1, 1, 1, 3, 5, 2, 2, 3, 2, 3, 1, 1, 1, 1, 1, 4, 2, 2, 3, 5, 2, 2, 2, 1, 2, 2, 4, 1, 1, 3
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OFFSET

2,1


LINKS

Table of n, a(n) for n=2..34.
M. Goetz, Welcome to the AP27 Search.


EXAMPLE

T(5, 3) = 4, because prime(5) = 11 and 11+2*3 = 17, 17+2*3 = 23, 23+2*3 = 29 are all prime, but 29+2*3 = 35 is composite, so 4 terms in the arithmetic progression of primes with common difference 6 starting at 11 are prime.
Table starts
3, 3, 1, 3, 3, 1, 3, 2
2, 1, 5, 2, 1, 5, 2, 1
1, 2, 3, 1, 2, 4, 1, 2
2, 1, 4, 2, 1, 2, 1, 1
1, 2, 2, 1, 2, 1, 1, 2
2, 1, 3, 1, 1, 4, 2, 1


PROG

(PARI) max_prog_len(initialp, diff) = my(i=1, p=initialp); while(ispseudoprime(p+diff), p=p+diff; i++); i
table(rows, cols) = for(n=2, rows+1, for(k=1, cols, print1(max_prog_len(prime(n), 2*k), ", ")); print(""))
table(6, 8) \\ print 6x8 table


CROSSREFS

Sequence in context: A100013 A065744 A016455 * A060574 A283987 A286443
Adjacent sequences: A278699 A278700 A278701 * A278703 A278704 A278705


KEYWORD

nonn,tabl,more


AUTHOR

Felix Fröhlich, Nov 26 2016


STATUS

approved



