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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, 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
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
KEYWORD
nonn,easy
AUTHOR
Gaël Collinet, Jun 08 2011
STATUS
approved