A191590 a(n) is the genus of the modular curve associated to the principal congruence subgroup of level p(n), where p(n) is the n-th prime number.

0, 0, 3, 26, 50, 133, 196, 375, 806, 1001, 1768, 2451, 2850, 3773, 5500, 7686, 8526, 11408, 13651, 14875, 18981, 22100, 27391, 35673, 40376, 42875, 48178, 50986, 56925, 81313, 89376, 102443, 107066, 132276, 137751, 155078, 173800, 187083, 208250, 230956, 238876, 281201

Offset

2,3

Links

Table of n, a(n) for n=2..43.

Jens Putzka, Aequivariante Signaturen und Darstellungen der Modulgruppe in der Kohomologie von Modulkurven, Master's Thesis (2006), page 18.

Formula

a(n) = (prime(n)+2)*(prime(n)-3)*(prime(n)-5)/24.

Prog

(PARI) a(p)=(p+2)*(p-3)*(p-5)/24;
forprime(p=3, 1000, print1(a(p), ", "));

Crossrefs

Sequence in context: A058993 A358352 A083109 * A354050 A177511 A294494

Adjacent sequences: A191587 A191588 A191589 * A191591 A191592 A191593

Keyword

nonn,easy

Author

Gaël Collinet, Jun 08 2011

Status

approved