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A145043 Primes p for which s=2 is the least positive integer such that sp-t(sp) is a triangular number, where t(n) is the maximal triangular number not exceeding n 2
5, 17, 23, 47, 53, 71, 73, 127, 173, 233, 251, 269, 281, 347, 353, 359, 431, 487, 491, 509, 541, 563, 569, 593, 613, 677, 743, 773, 827, 857, 863, 883, 929, 953, 977, 1013, 1153, 1187, 1283, 1319, 1361, 1373, 1439, 1481, 1583, 1613, 1619, 1709, 1871, 1997 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
PROG
(PARI) maxt(n) = {k = 1; while ((t=k*(k+1)/2) < n, k++); if (t == n, t, k--; k*(k+1)/2); }
lista(nn) = {forprime(p = 2, nn, if (! ispolygonal(p - maxt(p), 3) && ispolygonal(2*p - maxt(2*p), 3), print1(p, ", "); ); ); } \\ Michel Marcus, Jul 25 2014
CROSSREFS
Sequence in context: A236119 A141275 A303193 * A097434 A106012 A230527
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Sep 30 2008
EXTENSIONS
More terms from Michel Marcus, Jul 25 2014
STATUS
approved

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Last modified March 28 15:38 EDT 2024. Contains 371254 sequences. (Running on oeis4.)