[seqfan] Re: Coprime To Sums

Rick Shepherd rlshepherd2 at gmail.com
Sun Aug 30 22:24:21 CEST 2009


To answer your questions at least partially:
My A164901 calculations agree with yours.
The only composite among the first 202 terms is the term 4.
Here are these terms (I'll submit a larger b-file later unless someone else
does so first;
I would need to clean up a "quick-and-dirty" PARI program first to make it
more efficient):

[1, 2, 4, 7, 13, 19, 29, 37, 43, 53, 59, 67, 73, 79, 89, 97, 103, 109, 127,
137,
149, 157, 163, 173, 179, 191, 197, 211, 223, 229, 239, 251, 257, 263, 269,
277, 283, 293, 307, 313, 331, 337, 347, 353, 359, 367, 373, 379, 389, 397,
409, 419, 431, 439, 449, 457, 463, 479, 487, 499, 509, 521, 541, 547, 557,
563, 569, 577, 587, 593, 599, 607, 613, 619, 631, 641, 647, 653, 659, 673,
683, 691, 701, 709, 719, 727, 733, 739, 751, 757, 769, 787, 797, 809, 821,
827, 839, 853, 859, 877, 883, 907, 919, 929, 937, 947, 953, 967, 977, 983,
991, 997, 1009, 1019, 1031, 1039, 1049, 1061, 1069, 1087, 1093, 1103,
1109, 1117, 1123, 1129, 1151, 1163, 1171, 1181, 1187, 1193, 1201, 1213,
1223, 1229, 1237, 1249, 1259, 1277, 1283, 1289, 1297, 1303, 1319, 1327,
1361, 1367, 1373, 1381, 1399, 1409, 1423, 1429, 1439, 1447, 1453, 1459,
1471, 1481, 1487, 1493, 1499, 1511, 1523, 1531, 1543, 1549, 1559, 1567,
1579, 1597, 1607, 1613, 1619, 1627, 1637, 1657, 1663, 1669, 1693, 1699,
1709, 1721, 1733, 1741, 1747, 1753, 1759, 1777, 1783, 1789, 1801, 1811,
1823, 1831, 1847, 1861, 1867, 1873, 1879, 1889]

(I previously ran the program for much longer than it took to produce the
above output,
but interrupted that run and lost its array.  However, my code, which would
have printed
any additional composites, found none up to whatever, unknown point it
reached.)

Regards,
Rick



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