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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

Table of n, a(n) for n=1..50.

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

Cf. A000217, A145032, A145016, A145022, A145023.

Sequence in context: A154632 A236119 A141275 * A097434 A106012 A230527

Adjacent sequences:  A145040 A145041 A145042 * A145044 A145045 A145046

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 September 21 15:13 EDT 2017. Contains 292300 sequences.