OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..2049

FORMULA

If p is an odd prime then a(p) = 3.

EXAMPLE

a(6) = 4 because T_6(x)+1 = 32x^6-48x^4+18x^2 = x^2*(4x^2-3)^2.

PROG

(PARI) p2 = 1; p1 = x; for (n = 1, 103, p = 2*x*p1 - p2; f = factor(p1 + 1); print(sum(i = 1, matsize(f)[1], f[i, 2]), " "); p2 = p1; p1 = p); \\ David Wasserman, Mar 03 2005

(PARI) A086374(n) = {vecsum(factor(polchebyshev(n, 1, x)+1)[, 2])}; \\ Antti Karttunen, Sep 27 2018, after Andrew Howroyd's program for A086369

CROSSREFS

KEYWORD

nonn,easy

AUTHOR

Yuval Dekel (dekelyuval(AT)hotmail.com), Sep 06 2003

EXTENSIONS

More terms from David Wasserman, Mar 03 2005

STATUS

approved